Display device

ABSTRACT

An electroluminescent device includes a lower structure and a flexible encapsulation multilayer. The lower structure may have an emission area and a peripheral area surrounding the emission area. The flexible encapsulation multilayer may be disposed on the emission area and the peripheral area. The peripheral area may include an inorganic surface portion having a closed shape continuously surrounding the display area and comprising one or more inorganic materials. The flexible encapsulation multilayer may include a lower surface comprising only one or more inorganic materials. The lower surface of flexible encapsulation multilayer may be in in direction contact with the inorganic surface portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Application No.10-2017-0034772 filed on Mar. 20, 2017 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND 1. Field

One or more aspects of example embodiments of the present inventionrelate to an electroluminescent device.

2. Description of the Related Art

An organic light-emitting display includes an electroluminescent unitincluding a hole injection electrode, an electron injection electrode,and an organic light-emitting layer formed between the hole injectionelectrode and the electron injection electrode. The organiclight-emitting display is a self-emission type display device that emitslight when excitons, which are generated from the organic light-emittinglayer by the combination of holes injected from the hole injectionelectrode and electrons injected from the electron injection electrode,transition from an excited state to a ground state.

Because the organic light-emitting display device, which is aself-emission type display device, does not require an additional lightsource, it may be driven at a low voltage, may be a lightweight and thintype display device, and may have high quality characteristics, such asa wide viewing angle, high contrast, and rapid response speed.Therefore, the organic light-emitting display device is attractingconsiderable attention as a next-generation display device. However,because the electroluminescent unit may be deteriorated by externalmoisture and/or oxygen, it is desirable to prevent or block externalmoisture, oxygen, and/or the like from penetrating into theelectroluminescent unit.

The above information disclosed in this Background section is forenhancement of understanding of the background of the invention, andtherefore, it may contain information that does not constitute priorart.

SUMMARY

One or more aspects of the present invention provide are directed towardan electroluminescent device having improved encapsulatingcharacteristics.

According one or more aspects of the present invention, anelectroluminescent device may comprise a lower structure and a flexibleencapsulation multilayer. The lower structure may have an emission areaand a peripheral area surrounding the emission area. The lower structuremay comprise an inorganic insulating film, an insulation film located onthe inorganic insulating film, and an electroluminescent unit having alower electrode disposed on the insulation film, an intermediate filmdisposed on the lower electrode, and an upper electrode disposed on theintermediate film. The flexible encapsulation multilayer may be disposedon the emission area and the peripheral area, and may include at leastthree layers. The peripheral area may include an inorganic surfaceportion substantially surrounding the emission area, may be locatedoutside the upper electrode at a planar view, and may comprise only oneor more inorganic materials. The flexible encapsulation multilayer mayinclude a lower surface comprising only one or more inorganic materials.An entire of the inorganic surface portion may directly contact thelower surface of the flexible encapsulation multilayer. The lowerstructure may include a lower encapsulation inorganic film horizontallyexpanding under a surface of the lower structure to verticallycorrespond to the emission area and the peripheral area. A portiondisposed between the lower encapsulation inorganic film and the entireof the inorganic surface portion may comprise only one or more inorganicmaterials.

In one or more example embodiments, the inorganic surface portion mayinclude a first region having a first average width and a second regionhaving a second average width, and the first average width and thesecond average width may be substantially different from each other.

In one or more example embodiments, the first region and the secondregion may be located at the same side of the lower structure.

In one or more example embodiments, the first region of the inorganicsurface portion may entirely correspond to a first side of the lowerstructure, and the second region of the inorganic surface portion mayentirely correspond to a second side of the lower structure differentfrom the first side of the lower structure.

In one or more example embodiments, the first region may have a firstpart having a third average width relatively smaller than the firstaverage width and a second part having a fourth average width relativelylarger than the first average width.

In one or more example embodiments, the lower electrode may be disposeddirectly on a top surface of the insulation film, and the entire of theinorganic surface portion may be disposed relatively lower than the topsurface of the insulation film. The inorganic surface portion may haveat least a region including a plurality of inorganic surface branchesspaced from each other. The peripheral area may include an organicsurface portion which is disposed between the inorganic surfacebranches. The organic surface portion may comprise an organic materialand may substantially surround the emission area. The organic surfaceportion may be substantially surrounded at a planar view by an interfacewhere the lower surface of the flexible encapsulation multilayerdirectly contacts the inorganic surface portion. The inorganic surfacebranches may include an outer inorganic surface branch locatedrelatively outer than the organic surface portion and an inner inorganicsurface branch located relatively inner than the organic surfaceportion. The lower structure may further comprise a bus wire extendingon a top surface of the inorganic insulating film along a periphery ofthe emission area, and an auxiliary upper electrode which extends onside and top surfaces of the insulation film along the periphery of theemission area to electrically contact both a top surface of the bus wireand a bottom surface of the upper electrode. The inner inorganic surfacebranch may include at least a portion of a top surface of the auxiliaryupper electrode to have a height relatively larger than a height of theouter inorganic surface branch. A portion of a surface of the bus wiremay directly contact the lower surface of the flexible encapsulationmultilayer, and the portion of the surface of the bus wire may berelatively farther than the organic surface portion from the emissionarea.

In one or more example embodiments, the electroluminescent device may becapable of being flexed, bent, folded, rolled, or stretched by an enduser.

In one or more example embodiments, the inorganic surface portion mayinclude at least two stepped surface portions each including a topsurface portion of the inorganic insulating film, a side surface portionof the bus wire, and a top surface portion of the bus wire. The bus wiremay have an outer edge portion and an inner edge portion opposite to theouter edge portion. The outer edge portion of the bus wire may berelatively farther than the inner edge portion of the bus wire from theemission area and may be located under the bottom surface of theflexible encapsulation multilayer. The outer edge portion of the buswire may be not in direct contact with the bottom surface of theflexible encapsulation multilayer.

In one or more example embodiments, the inorganic surface portion mayfurther include at least two stepped surface portions each including atop surface portion of the inorganic insulating film, a side surfaceportion of the auxiliary upper electrode, and a top surface portion ofthe auxiliary upper electrode. The auxiliary upper electrode may have anouter edge portion and an inner edge portion opposite to the outer edgeportion. The outer edge portion of the auxiliary upper electrode may berelatively farther than the inner edge portion of the auxiliary upperelectrode from the emission area and may be located under the bottomsurface of the flexible encapsulation multilayer. The outer edge portionof the auxiliary upper electrode may be not in direct contact with thebottom surface of the flexible encapsulation multilayer.

In one or more example embodiments, the inorganic surface portion mayfurther include at least two stepped surface portions each including atop surface portion of the bus wire, a side surface portion of theauxiliary upper electrode, and a top surface portion of the auxiliaryupper electrode. The auxiliary upper electrode may have an outer edgeportion and an inner edge portion opposite to the outer edge portion.The outer edge portion of the auxiliary upper electrode may berelatively farther than the inner edge portion of the auxiliary upperelectrode from the emission area. The outer edge portion of theauxiliary upper electrode may be located under the bottom surface of theflexible encapsulation multilayer and may be not in direct contact withthe bottom surface of the flexible encapsulation multilayer.

In one or more example embodiments, the inorganic surface portion mayfurther include at least two stepped surface portions each including atop surface portion of the inorganic insulating film, a side surfaceportion of the auxiliary upper electrode, and a top surface portion ofthe auxiliary upper electrode. The inorganic surface portion may furtherinclude at least two stepped surface portions each including a topsurface portion of the bus wire, a side surface portion of the auxiliaryupper electrode, and a top surface portion of the auxiliary upperelectrode. The auxiliary upper electrode may have an outer edge portionand an inner edge portion opposite to the outer edge portion. The outeredge portion of the auxiliary upper electrode may be relatively fartherthan the inner edge portion of the auxiliary upper electrode from theemission area. The outer edge portion of the auxiliary upper electrodemay be located under the bottom surface of the flexible encapsulationmultilayer and may be not in direct contact with the bottom surface ofthe flexible encapsulation multilayer.

In one or more example embodiments, the portion of the surface of thebus wire, which directly contacts the lower surface of the flexibleencapsulation multilayer, may be included in the outer inorganic surfacebranch.

In one or more example embodiments, the organic surface portion may havea shape opened by an opening to discontinuously surround the emissionarea. The first region of the inorganic surface portion may entirelycorrespond to a first side of the lower structure at which the openingis disposed. The second region of the inorganic surface portion mayentirely correspond to a second side of the lower structure at which theopening is not disposed. The first average width of the first region maybe relatively larger than the second average width of the second region.

In one or more example embodiments, the peripheral area may include aninorganic structure having an edge having a lateral surface and an uppersurface. The inorganic surface portion may include the lateral and uppersurfaces of the edge. The lateral and upper surfaces of the edge maydirectly contact the flexible encapsulation multilayer. The edge mayextend from an outer edge of the inorganic surface portion to an inneredge of the inorganic surface portion located opposite to the outer edgeof the inorganic surface portion. The lateral surface of the edge mayinclude at least two independently selected from the group consisting ofa convex portion, a concave portion, an angled portion, a curvedportion, and a portion extending substantially along a direction inwhich the inorganic surface portion extends.

In one or more example embodiments, the inorganic structure may includea first inorganic film and a second inorganic film disposed on the firstinorganic film. A hardness of the second inorganic film may berelatively larger than a hardness of the first inorganic film.

In one or more example embodiments, the peripheral area may include aconductive film providing the electroluminescent unit with an electricalsignal, and having a hole which penetrates the conductive film, which islocated inward from an inner edge of the inorganic surface portion, andwhich is an alignment mark. The conductive film may be an auxiliaryupper electrode extending along a periphery of the emission area, andelectrically contacting the upper electrode.

In one or more example embodiments, the inorganic surface portion mayhave at least one recess. The recess may be a hole formed through afirst inorganic layer on a second inorganic layer such that a topsurface of the second inorganic layer is exposed through the hole andbecomes a bottom surface of the recess. The first inorganic layer maycomprise only one or more inorganic films, and the second inorganiclayer may comprise only one or more inorganic films.

In one or more example embodiments, the recess may have a protrusionhaving a height no more than a depth of the recess.

In one or more example embodiments, at least two of the recesses mayhave substantially different shapes in a plan view.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present invention willbecome more apparent to those skilled in the art from the followingdetailed description of the example embodiments with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic plan view showing a display device according to anexample embodiment of the present invention;

FIG. 2 is a sectional view taken along the line A1-A1′ of FIG. 1;

FIG. 3 is a sectional view showing a modified example of the flexibleencapsulation multilayer in the display device of FIG. 2;

FIG. 4 is a sectional view showing another modified example of theflexible encapsulation multilayer in the display device of FIG. 2;

FIG. 5 is an enlarged view of the area S of FIG. 1;

FIG. 6 is a sectional view taken along the line A2-A2′ of FIG. 5;

FIG. 7 is a sectional view showing a modified example of FIG. 6;

FIG. 8 is a sectional view showing another modified example of FIG. 6;

FIG. 9 is a sectional view taken along the line A3-A3′ of FIG. 5;

FIG. 10 is a sectional view taken along the line A4-A4′ of FIG. 1;

FIG. 11 is a view showing a modified example of FIG. 5;

FIG. 12 is a view showing another modified example of FIG. 5;

FIG. 13 is a schematic plan view showing a display device according toanother example embodiment of the present invention;

FIG. 14 is a sectional view taken along the line A5-A5′ of FIG. 13;

FIG. 15 is a sectional view showing a modified example of FIG. 14;

FIG. 16 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 17 is a sectional view taken along the line A6-A6′ of FIG. 16;

FIG. 18 is a sectional view showing a modified example of FIG. 17;

FIG. 19 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 20 is a sectional view taken along the line A7-A7′ of FIG. 19;

FIG. 21 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 22 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 23 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 24 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 25 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 26 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 27 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 28 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 29 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 30 is an enlarged view of the area T of FIG. 29;

FIG. 31 is a schematic plan view showing a display device according tostill another example embodiment of the present invention;

FIG. 32 is a schematic plan view showing a display device according tostill another example embodiment of the present invention; and

FIG. 33 is a schematic plan view showing a display device according tostill another example embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, example embodiments will be described in more detail withreference to the accompanying drawings, in which like reference numbersrefer to like elements throughout. The present invention, however, maybe embodied in various different forms, and should not be construed asbeing limited to only the illustrated example embodiments herein.Rather, these example embodiments are provided as examples so that thisdisclosure will be thorough and complete, and will fully convey theaspects and features of the present invention to those skilled in theart. Accordingly, processes, elements, and techniques that are notnecessary to those having ordinary skill in the art for a completeunderstanding of the aspects and features of the present invention maynot be described. Unless otherwise noted, like reference numerals denotelike elements throughout the attached drawings and the writtendescription, and thus, descriptions thereof may not be repeated.

In the drawings, the relative sizes of elements, layers, and regions maybe exaggerated and/or simplified for clarity. Spatially relative terms,such as “beneath,” “below,” “lower,” “under,” “above,” “upper,” and thelike, may be used herein for ease of explanation to describe one elementor feature's relationship to another element(s) or feature(s) asillustrated in the figures. It will be understood that the spatiallyrelative terms are intended to encompass different orientations of thedevice in use or in operation, in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” or “under” otherelements or features would then be oriented “above” the other elementsor features. Thus, the example terms “below” and “under” can encompassboth an orientation of above and below. The device may be otherwiseoriented (e.g., rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein should be interpretedaccordingly.

It will be understood that, although the terms “first,” “second,”“third,” etc., may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, a first element, component, region, layer or sectiondescribed below could be termed a second element, component, region,layer or section, without departing from the spirit and scope of thepresent invention.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to,” or “coupled to” another element or layer, itcan be directly on, connected to, or coupled to the other element orlayer, or one or more intervening elements or layers may be present. Inaddition, it will also be understood that when an element or layer isreferred to as being “between” two elements or layers, it can be theonly element or layer between the two elements or layers, or one or moreintervening elements or layers may also be present

The terminology used herein is for the purpose of describing particularexample embodiments and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a” and “an” are intendedto include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes,” and “including,” “has,” “have,”and “having,” when used in this specification, specify the presence ofthe stated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof. As used herein, the term “and/or” includes anyand all combinations of one or more of the associated listed items.Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

As used herein, the term “substantially,” “about,” and similar terms areused as terms of approximation and not as terms of degree, and areintended to account for the inherent variations in measured orcalculated values that would be recognized by those of ordinary skill inthe art. Further, the use of “may” when describing example embodimentsof the present invention refers to “one or more example embodiments ofthe present invention.” As used herein, the terms “use,” “using,” and“used” may be considered synonymous with the terms “utilize,”“utilizing,” and “utilized,” respectively. Also, the term “exemplary” isintended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which the present invention belongs. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present specification, and should not be interpreted in an idealizedor overly formal sense, unless expressly so defined herein.

The expression “it comprises only an inorganic material” refers to thatit comprises only one or more inorganic materials, not that it comprisesonly one inorganic material. Further, the expression “it comprises onlyan organic material” refers to that it comprises only one or moreorganic materials, not that it comprises only one organic material. Theterm of “‘element’ portion” refers to at least a portion of the entire‘element.’ For example, the term of “an inorganic surface portion”refers to at least a portion of the entire inorganic surface. Countingthe number of ‘element’ portions is possible when the ‘element’ portionsare separated from each other in a plan view such that merging the‘element’ portions into one ‘element’ portion is not possible.

Hereinafter, example embodiments of the present invention will bedescribed with reference to the attached drawings

FIG. 1 is a schematic plan view showing a display device according to anexample embodiment of the present invention. FIG. 2 is a sectional viewtaken along the line A1-A1′ of FIG. 1, in which a lower structure and aflexible encapsulation multilayer are separated from each other. FIG. 3is a sectional view showing a modified example of the flexibleencapsulation multilayer in the display device of FIG. 2. FIG. 4 is asectional view showing another modified example of the flexibleencapsulation multilayer in the display device of FIG. 2. FIG. 5 is anenlarged view of the area S of FIG. 1. FIG. 6 is a sectional view takenalong the line A2-A2′ of FIG. 5. FIG. 7 is a sectional view showing amodified example of FIG. 6. FIG. 8 is a sectional view showing anothermodified example of FIG. 6. FIG. 9 is a sectional view taken along theline A3-A3′ of FIG. 5. FIG. 10 is a sectional view taken along the lineA4-A4′ of FIG. 1.

Referring to FIGS. 1 to 4, a display device 1000 according to an exampleembodiment of the present invention, as shown in FIGS. 1 and 2, includesa lower structure 100 and a flexible encapsulation multilayer 210disposed on the lower structure 100.

The lower structure 100 is a display substrate including elements (orcomponents) for implementing (or displaying) an image, such as anelectroluminescent unit, and includes a display area DA for displayingan image and a peripheral area PA surrounding (e.g., located around) thedisplay area DA. In one or more example embodiments, the lower structure100 may be any one of a bendable display substrate, a foldable displaysubstrate, a rollable display substrate, a stretchable displaysubstrate, and a flexible display substrate.

The peripheral area PA of the lower structure 100 includes an inorganicsurface portion 30. The inorganic surface portion 30 refers to a portionof the surface of the lower structure 100 facing the flexibleencapsulation multilayer 210, which is located at the peripheral areaPA, and which comprises only one or more inorganic materials.

The inorganic surface portion 30 may include a surface of an inorganicinsulation film, a surface of a conductive inorganic wiring (forexample, a metal wiring), or both. The inorganic surface portion 30included in the peripheral area PA may have a closed shape thatsurrounds (e.g., continuously surround) the entire display area DA.Illustratively, assuming that the left lower corner of the lowerstructure 100 is a starting point with reference to FIG. 1, theinorganic surface portion 30 may include a portion extending along afirst direction x1, a portion extending along a second direction y1, aportion extending along an opposite direction x2 of the first directionx1, and a portion extending along an opposite direction y2 of the seconddirection y1, arranged sequentially along the counterclockwisedirection, and all of the portions may be continuous.

The flexible encapsulation multilayer 210 is formed on a surface (e.g.,an entire surface) of the lower structure 100 to cover both the displayarea DA and the peripheral area PA. Alternatively, the flexibleencapsulation multilayer 210 may be formed on the lower structure 100 tocover the entire display area DA and at least a part (or portion) of theperipheral area PA. The flexible encapsulation multilayer 210 protectsan electroluminescent element of the display area DA from externalmoisture and/or oxygen. The flexible encapsulation multilayer 210 mayhave at least one sandwich structure in which at least one organic filmis disposed between at least two inorganic films. In an exemplaryexample embodiment, the flexible encapsulation multilayer 210, as shownin FIG. 2, may include a first inorganic film 211, a second inorganicfilm 215 disposed on the first inorganic film 211, and an organic film213 disposed between the first inorganic film 211 and the secondinorganic film 215. The second inorganic film 215 may entirely cover theorganic film 213, and may not cover a lateral surface of the firstinorganic film 211.

The first inorganic film 211 and the second inorganic film 215 comprisean inorganic material. The inorganic material may be a metal oxideand/or a metal nitride. For example, the inorganic material may includesilicon oxide (SiO₂), silicon nitride (SiN_(x)), silicon oxynitride(SiON), aluminum oxide (Al₂O₃), titanium oxide (Ta₂O₅), hafnium oxide(HfO₂), zinc oxide (ZrO₂), or a combination thereof. The organic film213 comprises an organic material. Examples of the organic material mayinclude an acrylic resin, a methacrylic resin, polyisoprene, a vinylresin, an epoxy resin, a urethane resin, a cellulose resin, a peryleneresin, or a combination thereof.

However, the structure of the flexible encapsulation multilayer 210 isnot limited thereto.

FIGS. 3 and 4 show modified examples of the flexible encapsulationmultilayer 210 of FIG. 2. As shown in FIG. 3, a flexible encapsulationmultilayer 220 may include a first inorganic film 221, a first organicfilm 223 disposed on the first inorganic film 221, a second inorganicfilm 225 disposed on the first organic film 223 to completely cover thefirst organic film 223, a second organic film 227 disposed on the secondinorganic film 225, and a third inorganic film 229 disposed on thesecond organic film 227 to completely cover the second organic film 227.As shown in FIG. 3, the second inorganic film 225 may not cover thelateral surface of the first inorganic film 221, and the third inorganicfilm 229 may not cover the lateral surface of the first inorganic film221 and the lateral surface of the second inorganic film 225. However,the present invention is not limited thereto, and, in another exampleembodiment, the third inorganic film 229 may cover the lateral surfaceof the first inorganic film 221 and the lateral surface of the secondinorganic film 225.

As shown in FIG. 4, a flexible encapsulation multilayer 230 may includea first inorganic film 231, an organic film 233 disposed on the firstinorganic film 231, and a second inorganic film 235 disposed on theorganic film 233. The second inorganic film 235 may completely cover theorganic film 233, and may cover the lateral surface of the firstinorganic film 231.

All of the flexible encapsulation multilayers 210, 220 and 230,described with reference to FIGS. 2 to 4, have a multilayer structure,and the lower surface facing the lower structure 100 is a lower surfaceof the first inorganic films 211, 221 and 231. That is, all the lowersurfaces of the flexible encapsulation multilayers 210, 220 and 230comprise only one or more inorganic materials. The lower surface of eachof the flexible encapsulation multilayers 210, 220 and 230 comprisingonly one or more inorganic materials is in direct contact with theabove-described inorganic surface portion 30 of the lower structure 100to form an inorganic-inorganic junction. In other words, the lowersurface of each of the flexible encapsulation multilayers 210, 220 and230 is in direct contact with the inorganic surface portion 30 of thelower structure 100 to form a sealing region, and the sealing region isformed only by one or more inorganic materials.

When an organic material exists in the sealing region, it is difficultto prevent or substantially prevent moisture penetration. On the otherhand, in the case of the display device 1000, because the sealing regionis formed only by one or more inorganic materials, encapsulatingproperties may be improved.

Hereinafter, for convenience of explanation, a case where the displaydevice 1000 includes the flexible encapsulation multilayer 210 shown inFIG. 2 will be described in more detail as an example.

Referring to FIGS. 5 to 10, as shown in FIGS. 5 and 6, the peripheralarea PA of the lower structure 100 may include a substrate 101, a firstlower inorganic film 111 disposed on the substrate 101, a second lowerinorganic film 113 disposed on the first lower inorganic film 111, andan inorganic structure 40 disposed on the second lower inorganic film113.

The substrate 101 may support the entire display device 1000 andmaintain rigidity. The substrate 101 may have a flat or substantiallyflat upper surface, and may comprise a transparent insulating material.The substrate 101 may comprise a flexible material, for example, aplastic material, such as polyether sulfone (PES) and polyacrylate(PAR). On the other hand, the substrate 101 may comprise an opaquematerial, such as metal and carbon fiber. In order to realize a flexibledisplay device, the substrate 101 may also comprise a plastic material,such as a polyimide (PI) film. However, the present invention is notlimited thereto, and the substrate 101 may comprise glass or anysuitable material.

The first lower inorganic film 111 is formed on the substrate 101. Thefirst lower inorganic film 111 overlaps at least the display area DA.For example, the first lower inorganic film 111 may be formed under adisplay element, such as an electroluminescent unit, provided in thedisplay area DA, may be formed adjacent to the display element, or maybe formed adjacent to any one of members (or components) provided in thedisplay element.

The first lower inorganic film 111 is formed in the display area DA, andmay extend to a part (or portion) of the peripheral area PA. The firstlower inorganic film 111 may include any one of a buffer film, a gateinsulating film, and/or an interlayer insulating film, which will bedescribed in more detail below, but the present invention is not limitedthereto. In addition, the first lower inorganic film 111 may be a metalwiring.

The second lower inorganic film 113 may be formed on the first lowerinorganic film 111. Similarly to the first lower inorganic film 111, thesecond lower inorganic film 113 may be formed in the display area DA,and may extend to a part (or portion) of the peripheral area PA. In oneor more example embodiments, the second lower inorganic film 113 mayinclude various inorganic films, as long as it is located on the firstlower inorganic film 111. Illustratively, when the first lower inorganicfilm 111 is a buffer film to be described in more detail later, thesecond lower inorganic film 113 may be any one of a gate insulating filmand an interlayer insulating film, which will be described in moredetail later. However, the present invention is not limited thereto, andthe second lower inorganic film 113 may include various structurescomprising inorganic materials, for example, various metal wirings.

The inorganic structure 40 may be an inorganic insulating film or aconductive inorganic wiring (for example, a metal wiring).

The inorganic structure 40 may be in direct contact with the firstinorganic film 211 of the flexible encapsulation multilayer 210.

When viewed from a planar view, an edge of the inorganic structure 40may include a portion extending from an outer edge OE of the inorganicsurface portion 30 to an inner edge IE of the inorganic surface portion30. Further, the portion of the edge of the inorganic structure 40 mayinclude at least one of a convex portion 40 a 1 and a concave portion 40a 2. As described above, the inorganic structure 40 is in direct contactwith the first inorganic film 211 of the flexible encapsulationmultilayer 210, and a step is generated by the inorganic structure, sothat a void Vo may be formed between the first inorganic film 211 andthe inorganic structure 40.

When the inorganic structure 40 extends in the shape of a straight line,the void Vo also grows linearly in many cases. In this case, moisture,oxygen, and/or the like may penetrate into the display device 1000 fromthe outside through the void Vo.

On the other hand, in the case of the display device 1000, the edge ofthe inorganic structure 40 includes at least one of the convex portion40 a 1 and the concave portion 40 a 2. Thus, even when the void Vo isformed and grown around the edge of the inorganic structure 40 extendingalong the first direction x1, the void Vo is reduced or eliminated atthe side of the convex portion 40 a 1 or the concave portion 40 a 2.Particularly, when a plurality of the convex portions 40 a 1 or aplurality of the concave portions 40 a 2 are formed, the void Vo is morereliably reduced or eliminated. Accordingly, the encapsulatingreliability in the peripheral area PA may be improved.

The inorganic structure 40 may have a single-layer structure as shown inFIG. 6, but the present invention is not limited thereto.

FIGS. 7 and 8 show modified examples of the inorganic structure 40 ofFIG. 6.

Illustratively, as shown in FIG. 7, an inorganic structure 41 mayinclude a first inorganic film 411 disposed on the second lowerinorganic film 113 and a second inorganic film 413 disposed on the firstinorganic film 411.

In one or more example embodiments, a sidewall 411 a of the firstinorganic film 411 may have a shape that is inwardly recessed relativeto a sidewall 413 a of the second inorganic film 413. For example, whenthe first inorganic film 411 and the second inorganic film 413 arepatterned in order to form the inorganic structure 41, in a case wherethe etching rate of the first inorganic film 411 is relatively fasterthan the etching rate of the second inorganic film 413 corresponding toan etching solution used in wet etching, the sidewall 411 a of the firstinorganic film 411 may be recessed inward relative to the sidewall 413 aof the second inorganic film 413.

Alternatively, for example, when the first inorganic film 411 and thesecond inorganic film 413 are patterned by dry etching in order to formthe inorganic structure 41, in a case where the hardness of the firstinorganic film 411 is relatively lower than the hardness of the secondinorganic film 413, the sidewall 411 a of the first inorganic film 411may be recessed inward relative to the sidewall 413 a of the secondinorganic film 413.

Further, as shown in FIG. 8, an inorganic structure 42 may include afirst inorganic film 421 disposed on the second lower inorganic film113, a second inorganic film 423 disposed on the first inorganic film421, and a third inorganic film 425 disposed on the second inorganicfilm 423.

In one or more example embodiments, a sidewall 423 a of the secondinorganic film 423 may have a shape that is inwardly recessed relativeto a sidewall 421 a of the first inorganic film 421 and/or a sidewall425 a of the third inorganic film 425. When wet etching is performed inthe process of forming the inorganic structure 42, the shape of theinorganic structure 42 may be formed when the etching rate of the secondinorganic film 423 corresponding to the etching solution (e.g., anetching liquid) is relatively faster than the etching rate of the firstinorganic film 421 and/or the etching rate of the third inorganic film425.

Further, when dry etching is performed in the process of forming theinorganic structure 42, the above-described shape of the inorganicstructure 42 may be realized even when the hardness of the secondinorganic film 423 is relatively lower than the hardness of the firstinorganic film 421 and/or the hardness of the third inorganic film 425.

FIG. 9 is a sectional view taken along the line A3-A3′ of FIG. 5, andFIG. 10 is a sectional view taken along the line A4-A4′ of FIG. 1.

Referring to FIG. 9, a first adhesion increasing recess 50 a may beformed in the peripheral area PA. In one or more example embodiments,the first adhesion increasing recess 50 a may be formed by removing apart (or portion) of the inorganic structure 40. Therefore, a surface(e.g., an entire surface) exposed by the first adhesion increasingrecess 50 a comprises an inorganic material, and is included in theinorganic surface portion 30. More specifically, because the lateralsurface of the first adhesion increasing recess 50 a comprises the samematerial as that of the inorganic structure 40, both the lateral surfaceand the inorganic structure 40 comprise only one or more inorganicmaterials. Because a bottom surface of the first adhesion increasingrecess 50 a corresponds to the top surface of the partially exposedsecond lower inorganic film 113, both the bottom surface and the topsurface comprise an inorganic material. Accordingly, the area of theinorganic surface portion 30 contacting the first inorganic film 211 ofthe flexible encapsulation multilayer 210 increases, thereby furtherimproving encapsulating reliability.

In one or more example embodiments, a plurality of the first adhesionincreasing recesses 50 a may be formed in the inorganic structure 40,and may be disposed at uniform or substantially uniform intervals. Here,the phrase “substantially uniform intervals” refers to that the firstadhesion increasing recesses 50 a are disposed at approximately uniformintervals, not that the first adhesion increasing recesses 50 a aredisposed at completely equal intervals. Also, In one or more exampleembodiments, the first adhesion increasing recess 50 a may not bepresent in parts (or portions) of the peripheral area PA.

Referring to FIG. 10, a second adhesion increasing recess 50 b may beformed in the peripheral area PA. In one or more example embodiments,the second adhesion increasing recess 50 b may be formed by removing apart (or portion) of the second lower inorganic film 113. Therefore, asurface (e.g., an entire surface) exposed by the second adhesionincreasing recess 50 b comprises an inorganic material, and is includedin the inorganic surface portion 30. More specifically, because thelateral surface of the second adhesion increasing recess 50 b comprisesthe same material as the second lower inorganic film 113, both thelateral surface and the second lower inorganic film 113 comprise onlyone or more inorganic materials. Because a bottom surface of the secondadhesion increasing recess 50 b corresponds to a top surface of thepartially exposed first lower inorganic film 111, both the bottomsurface and the top surface comprise only one or more inorganicmaterials. Accordingly, the area of the inorganic surface portion 30contacting the first inorganic film 211 of the flexible encapsulationmultilayer 210 increases, thereby further improving encapsulatingreliability.

In one or more example embodiments, a plurality of the second adhesionincreasing recesses 50 b may be formed, and may be disposed at uniformor substantially uniform intervals. Here, the term “substantiallyuniform intervals” refers to that the second adhesion increasingrecesses 50 b are disposed at approximately uniform intervals, not thatthe second adhesion increasing recesses 50 b are disposed at completelyequal intervals. Also, In one or more example embodiments, the secondadhesion increasing recess 50 b may not be present in parts (orportions) of the peripheral area PA.

FIG. 11 is a view showing a modified example of FIG. 5, and FIG. 12 is aview showing another modified example of FIG. 5.

Referring to FIG. 11, an edge of an inorganic structure 43, unlike thatshown in FIG. 5, may include angled portions. For example, the edge ofthe inorganic structure 43, as shown in FIG. 11, may include a firstportion extending along the first direction x1, a second portionextending from the first portion along the opposite direction y2 of thesecond direction y1, and a third portion extending from the secondportion along the first direction x1. Here, the first portion and thesecond portion may form an angle (e.g., a predetermined angle)therebetween, and similarly, the second portion and the third portionmay form an angle (e.g., a predetermined angle) therebetween. Even whenthe inorganic structure 43 is provided with the angled portions in thisway, as shown in FIG. 11, an effect similar to that described above withreference to FIG. 6 occurs.

Referring to FIG. 12, an edge of an inorganic structure 44, unlike thatshown in FIG. 11, may include rounded portions. For example, the edge ofthe inorganic structure 44, as shown in FIG. 12, may include a firstportion extending along the first direction x1, a second portion fromthe first portion along the opposite direction y2 of the seconddirection y1, a third portion extending from the second portion alongthe first direction x1, a first connection portion, which is rounded,between the first portion and the second portion, and a secondconnection portion, which is rounded, between the second portion and thethird portion. Even when the inorganic structure 44 is provided with therounded portions as shown in FIG. 12, an effect similar to thatdescribed above with reference to FIG. 6 occurs.

FIG. 13 is a schematic plan view showing a display device according toanother example embodiment of the present invention, FIG. 14 is asectional view taken along the line A5-A5′ of FIG. 13, and FIG. 15 is asectional view showing a modified example of FIG. 14.

Referring to FIGS. 13 and 14, a display device 1001 includes a firstadhesion increasing recess 50 b 1 and a second adhesion increasingrecess 50 b 2 in the peripheral area PA. The first adhesion increasingrecess 50 b 1 may have a shape extending along an edge of the inorganicsurface portion 30. This first adhesion increasing recess 50 b 1 may beformed in a plurality.

The second adhesion increasing recess 50 b 2 may be located closer to(e.g., adjacent to) the display area DA, compared to the first adhesionincreasing recess 50 b 1, and may have a shape that continuouslysurrounds the display area DA. Although not shown in the drawings, thesecond adhesion increasing recess 50 b 2 may be formed in a plurality.Although both the first adhesion increasing recess 50 b 1 and the secondadhesion increasing recess 50 b 2 are shown as being formed in theperipheral area PA of the display device 1001, this is only one example.That is, In one or more example embodiments, any one of the firstadhesion increasing recess 50 b 1 and the second adhesion increasingrecess 50 b 2 may be omitted.

The extending direction of the first adhesion increasing recess 50 b 1is perpendicular or substantially perpendicular to a direction ofinfiltration of moisture and/or oxygen from the outside of the displaydevice 1001 towards a center of the display device 1001. Similarly, whenthe second adhesion increasing recess 50 b 2 has the shape thatcontinuously surrounds the display area DA, the extending direction ofthe second adhesion increasing recess 50 b 2 is perpendicular orsubstantially perpendicular to the direction of infiltration of moistureand/or oxygen from the outside of the display device 1001 towards thecenter of the display device 1001. Therefore, moisture and/or oxygen maynot infiltrate into the display device 1001.

Referring to FIG. 14, each of the first adhesion increasing recess 50 b1 and the second adhesion increasing recess 50 b 2 may be formed byremoving a part (or portion) of the inorganic structure 40, and a part(or portion) of the second lower inorganic film 113. Accordingly, thearea of the inorganic surface portion 30 may be effectively increasedand, thus, the contact area between the inorganic surface portion 30 andthe lower surface of the flexible encapsulation multilayer 210 and/orthe contact area between the inorganic surface portion 30 and the lowersurface of the first inorganic film 211 may be increased.

In one or more example embodiments, a stepped surface may be formed onthe bottom surfaces of the first adhesion increasing recess 50 b 1 andthe second adhesion increasing recess 50 b 2. The stepped surface may bea surface of a protrusion 70. The protrusion 70 may be a part (orportion) of the second lower inorganic film 113 and, thus, the area ofthe inorganic surface portion 30 may be further increased.

The height of the protrusion 70 that is measured based on the uppersurface of the first lower inorganic film 111 is relatively smaller thanthe depth of the first adhesion increasing recess 50 b 1. Although notshown in the drawings, a planar shape of the protrusion 70 may bevariously formed, such as a cross shape, a stripe shape, and/or thelike. However, the protrusion 70 having a portion extending in the sameor substantially the same direction as that of the edge of the inorganicsurface portion 30, regardless of whether it has a cross shape or astraight shape, may be more effective at preventing or reducinginfiltration of moisture and/or oxygen, because it allows at least theportion of the protrusion 70 to be perpendicular or substantiallyperpendicular to the direction of infiltration of moisture and/or oxygenfrom the lateral side of the display device towards the center of thedisplay device.

In one or more example embodiments, a protrusion 70 a, as shown in FIG.15, may be further disposed on the protrusion 70. The protrusion 70 amay be a part (or portion) of the inorganic structure 40.

The height of the protrusion 70 a that is measured based on the uppersurface of the first lower inorganic film 111 may be equal orsubstantially equal to the height of the inorganic structure 40 that ismeasured based on the upper surface of the first lower inorganic film111. In this case, the first adhesion increasing recess 50 b 1,described with reference to FIG. 14, may be divided into firstsub-adhesion increasing recesses 50 b 1 a and 50 b 1 b, and the secondadhesion increasing recess 50 b 2, described with reference to FIG. 14,may be divided into second sub-adhesion increasing recesses 50 b 2 a and50 b 2 b. Detailed description of the shape of the protrusion 70 a anddetailed description of the effect due to the protrusion 70 a will beomitted because they are the same or similar to those of the protrusion70 described above with reference to FIGS. 13 and 14.

FIG. 16 is a schematic plan view showing a display device according tostill another example embodiment of the present invention, FIG. 17 is asectional view taken along the line A6-A6′ of FIG. 16, and FIG. 18 is asectional view showing a modified example of FIG. 17.

Referring to FIGS. 16 to 18, when viewed from a planar view, in adisplay device 1002, the width of a long side or a portion extendingalong the y1-y2 directions (hereinafter, referred to as “a firstextending portion”) of the display device 1002 in the inorganic surfaceportion 30 and the width of a short side or a portion extending alongthe x1-x2 directions (hereinafter, referred to as “a second extendingportion”) of the display device 1002 in the inorganic surface portion 30are different from each other. In more detail, a first width W1 measuredin the x1-x2 directions at the first extending portion in the inorganicsurface portion 30 is relatively greater than a second width W2 measuredin the y1-y2 directions at the second extending portion in the inorganicsurface portion 30.

When the display device 1002 is embodied as a flexible display devicehaving flexibility, the display device 1002 may be bent and unbent(e.g., spread) many times. In this case, the stress applied to the longside of the display device 1002 may be relatively greater than thestress applied to the short side of the display device 1002. Therefore,the void Vo between the flexible encapsulation multilayer 210 and thelower structure 100 may occur at the long side of the display device1002. Accordingly, the encapsulating properties may be improved byhaving the first width W1 of the first extending portion of theinorganic surface portion 30 to be relatively greater than the secondwidth W2 of the second extending portion of the inorganic surfaceportion 30.

Because the side of the inorganic surface portion 30 may have aplurality of bent portions, it may be desirable for the first width W1to be calculated as an average width. That is, the value obtained bydividing the area SA of the first extending portion of the inorganicsurface portion 30 by the length L1 measured in the y1-y2 directions atthe first extending portion may determine the first width W1 of thefirst extending portion. Here, the area SA of the first extendingportion refers to an area viewed from a planar view.

The lower structure 100 of the display device 1002 includes a lowerencapsulation inorganic film which horizontally extends under thesurface portion of the lower structure 100 to vertically correspond tothe display area DA and the peripheral area PA. Because a structurecomprising an organic material is not interposed in the portion betweenthe inorganic surface portion 30 of the display device 1002 and thelower encapsulation inorganic film, the portion between the inorganicsurface portion 30 of the display device 1002 and the lowerencapsulation inorganic film comprises only one or more inorganicmaterials. Here, the lower encapsulation inorganic film may be any oneselected from the inorganic films 111, 113 and 115. Here, at least oneinorganic material may include SiN and/or SiON for improvingencapsulating properties.

Hereinafter, a configuration of the display device 1002 will bedescribed in more detail, and repeat description with that describedabove will be simplified or omitted.

The display device 1002 includes a substrate 101, a thin film transistorTFT formed the substrate 101, an electroluminescent unit EU connected tothe thin film transistor TFT, and a flexible encapsulation multilayer210 for encapsulating the electroluminescent unit EU.

As described above, the display device 1002 is divided into a displayarea DA and a peripheral area PA surrounding (e.g., located around) thedisplay area DA. The display area DA is disposed at (or near) the centerof the substrate 101, and is an area where an image is displayed. Theperipheral area PA is disposed at an edge of the substrate 101 tosurround the display area DA, and is an area where no image isdisplayed.

The substrate 101 may support the display device (e.g., the entiredisplay device) 1002 and may maintain or substantially maintainrigidity. The substrate 101 may comprise a transparent insulatingmaterial, and may have flexibility.

A plurality of electroluminescent units EU, which emit light fordisplaying an image, are disposed for each pixel on a portion of thesubstrate 101 corresponding to the display area DA. An upper electrodepower supply wire 901 for applying an electric signal or power to anupper electrode 125 of the electroluminescent unit EU disposed in thedisplay area DA is disposed in the peripheral area PA. The upperelectrode power supply wire 901 includes a bus wire 109 b and anauxiliary upper electrode 106 c. Hereinafter, components disposed in thedisplay area DA and the peripheral area PA will be described in order oflamination from the substrate 101.

A buffer film 111 is formed on the substrate 101. The buffer film 111smooths the upper surface of the substrate 101, and blocks or reducesthe infiltration of impurities. The buffer film 111 may be a multilayeror a single layer and may comprise an inorganic material, such assilicon oxide (SiO_(x)), silicon oxynitride and/or silicon nitride(SiN_(x)). The buffer film 111 may be formed by various depositionmethods. The buffer film 111 may be omitted, if desired.

A pixel circuit C1 is formed on the buffer film 111. The pixel circuitC1 includes at least one thin film transistor TFT. The thin filmtransistor TFT is electrically connected to the electroluminescent unitEU to drive the electroluminescent unit EU. Although not shown in thedrawings, the pixel circuit C1 may further include at least onecapacitor.

The thin film transistor TFT may be a top gate type thin filmtransistor, which sequentially includes an active layer 102, a gateelectrode 103, a source electrode 105, and a drain electrode 107.However, this is only one example, and the thin film transistor TFT maybe formed as various suitable types, such as a bottom gate type.Hereinafter, a case where the thin film transistor TFT is a top gatetype thin film transistor will be described in more detail, as anexample.

The active layer 102 is formed on the buffer film 111. The active layer102 may contain a semiconductor material, for example, amorphous siliconor poly crystalline silicon. However, the present invention is notlimited thereto, and the active layer 102 may contain an oxidesemiconductor material, for example,G-I-Z-O[(In₂O₃)_(a)(Ga₂O₃)_(b)(ZnO)_(c)] (where a, b, and c are realnumbers satisfying the conditions of a≥0, b≥0, and c>0, respectively).The active layer 102 may contain an oxide from among any one selectedfrom 12, 13, and 14 group metal elements. Examples of the oxide maycomprise zinc (Zn), indium (In), gallium (Ga), tin (Sn), cadmium (Cd),germanium (Ge), hafnium (Hf), or a combination thereof. The active layer102 includes a source region in contact with the source electrode 105, adrain region in contact with the drain electrode 107, and a channelregion located between the source region and the drain region. When theactive layer 102 contains amorphous silicon or polycrystalline silicon,the source region and the drain region may be doped with impurities, ifdesired.

A gate insulating film 112 is formed on the active layer 102, and may bea multilayer or a single layer and may comprise an inorganic material,such as silicon oxide (SiO_(x)), silicon oxynitride and/or siliconnitride (SiN_(x)). The gate insulating film 112 may insulate the activelayer 102 from the gate electrode 103.

The gate electrode 103 is formed on the gate insulating film 112. Thegate electrode 103 is connected to a gate line for applying an on/offsignal to the thin film transistor TFT. The gate electrode 103 maycomprise a low-resistance metal material. The gate electrode 103 may bea multilayer or a single layer and may comprise a conductive materialincluding molybdenum (Mo), aluminum (Al), copper (Cu), and/or titanium(Ti).

An interlayer insulating film 113 is formed on the gate electrode 103.The interlayer insulating film 113 may insulate the source electrode 105and the drain electrode 107 from the gate electrode 103. The interlayerinsulating film 113 may be a multilayer or a single layer and maycomprise an inorganic material, such as metal oxides and metal nitrides.For example, the inorganic material may include silicon nitride (SiN),silicon oxynitride (SiON), aluminum oxide (Al₂O₃), titanium oxide(TiO₂), tantalum oxide (Ta₂O₅), hafnium oxide (HfO₂), zinc oxide (ZrO₂),or a combination thereof.

The source electrode 105 and the drain electrode 107 are formed on theinterlayer insulating film 113. The source electrode 105 and the drainelectrode 107 are in contact with the source region and drain region,respectively, of the active layer 102 through contact holes formed inthe interlayer insulating film 113 and the gate insulating film 112. Aplanarization film 115 is formed on the thin film transistor TFT formedin this way. The planarization film 115 may be a single layer or amultilayer and may comprise an organic material, such as general purposepolymers. Examples of the organic material may comprisepolymethylmethacrylate (PMMA), polystyrene (PS), and/or polymerderivatives having a phenolic group, acrylic polymers, imide polymers,aryl ether polymers, amide polymers fluorine polymers, p-xylenepolymers, and/or vinyl alcohol polymers. The planarization film 115 mayeliminate or reduce steps on the top surface caused by a thin filmtransistor (TFT) array and may make the top surface thereof flat,thereby preventing or reducing the occurrence of defects in theelectroluminescent unit EU due to unevenness of a layer below theelectroluminescent unit EU.

The electroluminescent unit EU is formed at a portion of an uppersurface of the planarization film 115, the portion corresponding to thedisplay area DA. The electroluminescent unit EU includes a lowerelectrode 121, an upper electrode 125 facing the lower electrode 121,and an electroluminescent layer 123 disposed between the lower electrode121 and the upper electrode 125. The lower electrode 121 may be disposedon the planarization film 115 and may penetrate the planarization film115 to be connected to the drain electrode 107.

The electroluminescent layer 123 may contain an organic material. Thedisplay device may be classified as a bottom emission type, a topemission type, or a dual emission type according to an emissiondirection of the electroluminescent unit EU. In the bottom emission typedisplay device, the lower electrode 121 is provided as a transparent orsemitransparent electrode, and the upper electrode 125 is provided as areflective electrode. In the top emission type display device, the lowerelectrode 121 is provided as a reflective electrode, and the upperelectrode 125 is provided as a transparent or semitransparent electrode.In the dual emission type display device, both the lower electrode 121and the upper electrode 125 may be provided as transparent orsemitransparent electrodes.

When the lower electrode 121 functions as an anode, the lower electrode121 may contain a conductive material having a high work function.Examples of the conductive material may comprise indium tin oxide (ITO),indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (InO₃), indiumgallium oxide (IGO), aluminum zinc oxide (AZO), or a combinationthereof. The lower electrode 121 may be patterned in an island shapecorresponding to each pixel. Further, the lower electrode 121 may beconnected to the drain electrode 107 of the thin film transistor TFT toreceive an electric current.

A pixel defining layer (PDL) 117 for covering a portion (e.g., an edgeportion) of the lower electrode 121 may be formed on the lower electrode121. The pixel defining layer 117 may comprise one or more organicinsulating materials. Examples of the one or more organic insulatingmaterials may comprise polyimide, polyamide, acrylic resin,benzocyclobutene, phenol resin or a combination thereof. The pixeldefining layer 117 may be formed by a spin coating method or the like.An opening (e.g., a predetermined opening) for defining a pixel isformed in the pixel defining layer 117. The electroluminescent layer 123is formed at least in a region defined by the opening. In some exampleembodiments of the present invention, the pixel defining layer 117 isused to form a light-emitting layer by a solution technique, such as inkjet printing, nozzle printing, and the like, and may function as abarrier having a relatively high height.

The electroluminescent layer 123 may contain a low-molecular organicmaterial and/or a high-molecular organic material, which may emit red,green, or blue light. Although not shown in the drawings, a holetransport layer (HTL) and/or a hole injection layer (HIL) may bedisposed between the electroluminescent layer 123 and the lowerelectrode 121. Further, although not shown in the drawings, an electrontransport layer (ETL) and/or an electron injection layer (EIL) may bedisposed between the electroluminescent layer 123 and the upperelectrode 125. Of course, various layers other than the hole injectinglayer, the hole transporting layer, the electron transporting layer, andthe electron injecting layer may be laminated as needed.

Meanwhile, in the above description, a case where the electroluminescentlayer 123 is formed separately for each pixel has been described as anexample. In this case, red, green, and/or blue light may be respectivelyemitted for each pixel, and a pixel group for emitting red, green, andblue light may form one unit pixel. However, the present invention isnot limited thereto, and an organic light-emitting layer may be formedin common over the entire pixel. For example, a plurality of organiclight emitting layers for emitting red, green, and blue light may bevertically laminated or mixed to emit white light. However, the colorcombination for emitting white light is not limited thereto. In thiscase, a color conversion layer or color filter for converting theemitted white light into a color (e.g., a predetermined color) may beprovided.

The upper electrode 125 may comprise a conductive inorganic material.When the upper electrode 125 functions as a cathode, for example, it maycomprise Al, Mg, Ag, or the like, which has a low work function. Theupper electrode 125 may be formed as a common electrode over the displayarea (e.g., the entire display area DA), in which an image is displayed.In this case, the upper electrode 125 may be formed by an evaporationprocess that does not damage the electroluminescent layer 123.Meanwhile, the polarities of the lower electrode 121 and the upperelectrode 125 may be opposite to each other.

The upper electrode 125 is connected to an upper electrode power supplywire 901 that is disposed in the peripheral area PA to receive anelectric signal or power. The upper electrode power supply wire 901includes a bus wire 109 b and an auxiliary upper electrode 106 c.

The bus wire 109 b applies an externally supplied electric signal orpower to the upper electrode 125. Therefore, the bus wire 109 bcomprises a conductive inorganic material that may sufficiently conductan electric current. For example, the bus wire 109 b may be a singlelayer or a multilayer and may comprise one or more metals. Examples ofthe one or more metals may comprise aluminum (Al), platinum (Pt),palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni),neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca),molybdenum (Mo), titanium (Ti), tungsten (W), copper (Cu), or acombination thereof. The bus wire 109 b is formed on the interlayerinsulating film 113. The bus wire 109 b may be formed concurrently(e.g., at the same time) when the source electrode 105 and the drainelectrode 107 of the pixel thin film transistor TFT are formed. In thiscase, the bus wire 109 b may comprise the same conductive inorganicmaterial as the source electrode 105 and the drain electrode 107.

The bus wire 109 b should be electrically connected to the upperelectrode 125. However, the bus wire 109 b and the upper electrode 125are spaced from each other because they are formed on different layersfrom each other. Therefore, the auxiliary upper electrode 106 c forelectrically connecting the bus wire 109 b and the upper electrode 125is further included.

The auxiliary upper electrode 106 c is in contact with each of the buswire 109 b and the upper electrode 125 to transmit an electric signal orpower supplied from the bus wire 109 b to the upper electrode 125. Theauxiliary upper electrode 106 c serves as a bridge or a link. Therefore,the auxiliary upper electrode 106 c comprises a conductive inorganicmaterial that may conduct a sufficient electric current. For example,the auxiliary upper electrode 106 c may be a single layer or amultilayer and may comprise one or more metals. Examples of the one ormore metals may comprise aluminum (Al), platinum (Pt), palladium (Pd),silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd),iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum(Mo), titanium (Ti), tungsten (W), copper (Cu), or a combinationthereof. Meanwhile, a lateral surface portion of the planarization film115 is disposed in the peripheral area PA, and the auxiliary upperelectrode 106 c is disposed along the lateral surface and upper surfaceof the planarization film 115. According to an example embodiment of thepresent invention, the auxiliary upper electrode 106 c may be formed ofthe same or substantially the same material as the lower electrode 121,and may be formed concurrently (e.g., together) with the lower electrode121.

The auxiliary upper electrode 106 c may have a shape extending along theperiphery of the display area DA in the peripheral area PA. In moredetail, the auxiliary upper electrode 106 c has a shape surrounding orsubstantially surrounding the display area DA in the peripheral area PA,when viewed from a planar view, thereby preventing or reducing the IRdrop of the upper electrode 125. In relation to the shape of theauxiliary upper electrode 106 c, the terms “shape surrounding thedisplay area DA” or “shape substantially surrounding the display areaDA” includes a shape that partially surrounds the display area DA aswell as a shape that entirely surrounds the display area DA, so long asthere is an IR drop prevention or reduction effect. In order to increasethe area of a contact region between the auxiliary upper electrode 106 cand the bus wire 109 b, the bus wire 109 b may have a shape extendingalong the periphery of the display area DA in the peripheral area PA. Inmore detail, the bus wire 109 b may also have a shape surrounding orsubstantially surrounding the display area DA in the peripheral area PA.

The flexible encapsulation multilayer 210 is formed on the substrate(e.g., the entire substrate) 101 to cover both the display area DA andthe peripheral area PA. Alternatively, the flexible encapsulationmultilayer 210 may be formed on the substrate 101 to cover the displayarea (e.g., the entire display area) DA and at least a part (or portion)of the peripheral area PA. The flexible encapsulation multilayer 210protects the electroluminescent unit EU from external moisture, oxygen,and/or the like. The flexible encapsulation multilayer 210 may include afirst inorganic film 211, an organic film 213 disposed on the firstinorganic film 211, and a second inorganic film 215 disposed on theorganic film 213. Here, the organic film 213 allows the surface of thesecond inorganic film 215 to have a flat or substantially flat area FA.

In addition, the flexible encapsulation multilayer 210 may have variousstructures. Illustratively, the flexible encapsulation multilayer 210may sequentially include a first inorganic layer, a first organic layer,a second inorganic layer, a second organic layer, and a third inorganiclayer, from a top of the electroluminescent unit EU. Alternatively, theflexible encapsulation multilayer 210 may sequentially include a firstinorganic layer, a first organic layer, a second inorganic layer, asecond organic layer, a third inorganic layer, a third organic layer,and a fourth inorganic layer, from the top of the organic light emittingelement. Here, the first organic layer may have a relatively smallerarea than the second inorganic layer, and the second organic layer mayhave a relatively smaller area than the third inorganic layer. Further,the first organic layer may be completely covered by the secondinorganic layer, and the second organic layer may be completely coveredby the third inorganic layer. Further, because the area of the thirdinorganic layer is relatively larger than the areas of the firstinorganic layer, the first organic layer, the second inorganic layer,and the second organic layer, the third inorganic layer may cover theedges of the first inorganic layer, the first organic layer, the secondinorganic layer, and the second organic layer. As described above, theflexible encapsulation multilayer 210 may have various structures, butthe lower surface of the flexible encapsulation multilayer 210 maycomprise only one or more inorganic materials.

The flexible encapsulation multilayer 210 may protect theelectroluminescent unit EU included in the display area DA from externalmoisture and/or oxygen even when the flexible encapsulation multilayer210 alone encapsulates the lower structure 100. That is, a displaydevice that is reliable against the infiltration of external moistureand/or oxygen may be realized by allowing the flexible encapsulationmultilayer 210 alone to encapsulate the electroluminescent unit EUwithout using another additional encapsulating member that may preventor reduce the infiltration of moisture and/or oxygen. The flexibleencapsulation multilayer 210 may include a plurality of films. However,the present invention is not limited thereto, and the term “flexibleencapsulation multilayer 210” may also refer to a single layer havingexcellent encapsulating ability, and is included in the scope of thepresent invention.

The peripheral area PA has an inorganic surface portion 30 of a closedshape surrounding (e.g., continuously surrounding) the display area DA.The inorganic surface portion 30 is in direct contact with the lowersurface of the flexible encapsulation multilayer 210. Because theinorganic surface portion 30 contains only one or more inorganicmaterials and the lower surface of the flexible encapsulation multilayer210 contains only one or more inorganic materials, the direct bonding ofthe inorganic surface portion 30 and the lower surface of the flexibleencapsulation multilayer 210 forms an inorganic-inorganic directbonding.

The lower structure 100 has a lower encapsulation inorganic filmextending to vertically correspond to the display area DA and theperipheral area PA under the surface portion of the lower structure 100,and a portion of the lower structure 100 disposed between the inorganicsurface portion 30 and the lower encapsulation inorganic film maycontain only one or more inorganic materials. The lower encapsulationinorganic film may include, for example, a buffer film 111, a gateinsulating film 112, and/or an interlayer insulating film 113. Here, thelower encapsulation inorganic film may contain silicon nitride or/orsilicon oxynitride having a relatively low moisture and/or oxygenpermeability. The lower encapsulation inorganic film may contain atleast one hole that is filled with an inorganic material that isdifferent from the inorganic material contained in the lowerencapsulation inorganic film.

The upper portion of the display device is encapsulated by the flexibleencapsulation multilayer 210, the lower portion of the display device isencapsulated by the lower encapsulation inorganic film, such as thebuffer film 111, the gate insulating film 112, and/or the interlayerinsulating film 113, and the lateral portion of the display device isencapsulated by the portion containing only one or more inorganicmaterials and disposed between the inorganic surface portion 30 and thelower encapsulation inorganic film such the buffer film 111, the gateinsulating film 112, and/or the interlayer insulating film, therebyachieving a complete encapsulating structure.

As described above, the planarization film 115 may comprise an organicmaterial. An inorganic film formed by a deposition process, such aschemical vapor deposition (CVD), physical vapor deposition (PVD), andthe like, is difficult to realize a planarized upper surface as comparedto an organic film formed by a solution process, such as spin coating,ink jet coating, and the like. Therefore, when forming the planarizationfilm 115 by using an inorganic film, there is a problem that the heightof the planarization film 115 should be increased by laminating arelatively large number of inorganic layers or should be increased evenby a single inorganic film. Thus, it is preferred that the planarizationfilm 115 comprises an organic material. Accordingly, an organic materialis interposed between the inorganic surface of the auxiliary upperelectrode 106 c and the lower encapsulation inorganic film, such as thebuffer film 111, the gate insulating film 112 and the interlayerinsulating film 113. Therefore, the inorganic surface portion 30 may notbe formed in the region where the planarization film 115 is formed. As aresult, according to example embodiments of the present invention, theinorganic surface portion 30 is located relatively lower than the uppersurface of the planarization film 115. Here, the term “locatedrelatively lower” includes the term “located relatively closer” to thesubstrate 101.

FIG. 18 is a sectional view showing a modified example of FIG. 17. Thestructure of FIG. 18 is substantially different from the structure ofFIG. 17 in that the structure of FIG. 18 further includes an inorganicfilm 114. However, other features shown in FIG. 18 is the same orsubstantially the same as those of FIG. 17, and therefore, repeateddescription may be omitted.

The bus wire 109 b overlaps with the inorganic surface portion 30. Inthis specification, the meaning of “overlap” includes not only a casewhere the bus wire 109 b is included in the inorganic surface portion 30to be in contact with the bottom surface of the flexible encapsulationmultilayer 210 as shown in FIG. 17, but also includes a case where thebus wire 109 b vertically corresponds to the inorganic surface portion30 without being in contact with the bottom surface of the flexibleencapsulation multilayer 210 as shown in FIG. 18. That is, the term“overlap” includes a case where the bus wire 109 b is located beneaththe inorganic surface portion 30.

FIG. 19 is a schematic plan view showing a display device according tostill another example embodiment of the present invention, and FIG. 20is a sectional view taken along the line A7-A7′ of FIG. 19. Referring toFIGS. 19 and 20, a display device 1003 according to this exampleembodiment is the same or substantially the same as the above-describeddisplay device (e.g., 1002 shown in FIGS. 16 and 17), except for anorganic surface portion Os.

Referring to FIG. 19, the inorganic surface portion 30 is divided into afirst inorganic surface branch SA1 and a second inorganic surface branchSA2 at a first side of the lower structure 100. Illustratively, thefirst side refers to a left side of the lower structure 100 when viewedin a planar view, that is, a side in the x2 direction.

Here, a width W1 of the inorganic surface portion 30 at the first sidemay be obtained by dividing the sum of the area of the first inorganicsurface branch SA1 and the area of the second inorganic surface branchSA2 by the length L1 of the inorganic surface portion 30 at the firstside. When the device is manufactured as shown in FIG. 19, the width W1may also be calculated as the sum of the width W1 a of the firstinorganic surface branch SA1 and the width W2 a of the second inorganicsurface branch SA2. This calculation method may be applied to the aboveexample embodiment described with reference to FIG. 16, and may also beapplied to one or more example embodiments to be described later withreference to FIGS. 21 to 26.

Although it is shown in FIG. 19 that each of the length of the firstinorganic surface branch SA1 in the y1-y2 directions and the length ofthe second inorganic surface branch SA2 in the y1-y2 directions is equalor substantially equal to the length L1 of the inorganic surface portion30 at the first side, each of the length of the first inorganic surfacebranch SA1 in the y1-y2 directions and the length of the secondinorganic surface branch SA2 in the y1-y2 directions may be relativelyshorter than the length L1 of the inorganic surface portion 30 at thefirst side. Further, the shape of the organic surface portion Os may bethe same or substantially the same shape as a circle in a plan view.

The inorganic surface portion 30 may have a region diverging into theplurality of inorganic surface branches SA1 and SA2 that are spaced fromeach other. The peripheral region PA may include the organic surfaceportion Os disposed between the inorganic surface branches SA1 and SA2.

The organic surface portion Os may have a shape protruding upward.Because the organic surface portion Os overlaps with the organic film213 of the flexible encapsulation multilayer 210 while having a shapeprotruding upward, the organic surface portion Os may increase thebonding force with the lower structure 100 at the edge of the flexibleencapsulation multilayer 210. Further, when the height of the organicsurface portion Os is relatively high, the organic surface portion Osmay function as a dam to prevent or reduce the organic film 213 frombeing pushed to the outside by the thermal or physical stress applied tothe organic film 213 of the flexible encapsulation multilayer 210.

FIG. 21 is a schematic plan view showing a display device according tostill another example embodiment of the present invention.

Referring to FIG. 21, a display device 1004 is configured such that theinorganic surface portion 30 has a first width W1 at a first side (or anx2 direction side) having a relatively long length, and has a secondwidth W2, which is relatively larger than the first width W1, at asecond side (or a y2 direction side) having a relatively short length.When the display device 1004 is realized as a flexible display device,the degree of bending and unbending (e.g., spreading) at the long sidemay be relatively smaller than the degree of bending and unbending(e.g., spreading) at the short side, if desired. In this case, becausethe passing of oxygen and/or moisture between the flexible encapsulationmultilayer and the lower structure may more easily occur at the shortside compared to at the long side, an effective encapsulating may beachieved by forming the inorganic surface portion 30 to have a largerwidth at the short side. Because other descriptions of the displaydevice 1004 are substantially the same as those described above withreference to FIGS. 16 and 17, they will be omitted.

FIG. 22 is a schematic plan view showing a display device according tostill another example embodiment of the present invention.

Referring to FIG. 22, a display device 1005 is different from thedisplay device 1002 shown in FIGS. 16 and 17, in that the second side(or y2 direction side) of the inorganic surface portion 30 is fixed by arigid member RM. Other configurations are the same or substantiallysame, and thus, repeated description may be omitted.

The rigid member RM is a handle or the like of a display device, and maybe disposed only on one side (e.g., the y2 direction side) of thedisplay device 1005 as shown in FIG. 22. Although not show in thedrawings, two or more rigid members RM may be provided and fixed at bothsides (e.g., the y1 direction side and the y2 direction side) of thedisplay device 1005. Generally, because the degree of bending andunbending (e.g., spreading) of the rigid member RM at the fixed side isrelatively lower than the degree thereof at the other sides, relatively,the passing of moisture and/or oxygen may be prevented or reduced, andthus, the width W2 of the inorganic surface portion 30 at the side(e.g., the y2 direction side) fixed by the rigid member RM is relativelysmaller than the width W1 of the inorganic surface portion 30 at theother sides (e.g., the x1 direction side or the x2 direction side) notfixed by the rigid member RM, thereby obtaining effective encapsulating.

FIG. 23 is a schematic plan view showing a display device according tostill another example embodiment of the present invention.

Referring to FIG. 23, a display device 1006 is different from thedisplay device 1004 shown in FIG. 22, in that the width W2 of theinorganic surface portion 30 at the second side (or the y2 directionside) fixed by the rigid member RM is relatively larger than the widthW1 of the inorganic surface portion 30 at the side (e.g., the x1direction side or the x2 direction side) not fixed by the rigid memberRM. Other configurations are the same or substantially same, and thus,repeated description may be omitted.

In order to increase the area of the display area DA, there may be alimitation in increasing the width of the side on which the rigid memberRM is not fixed. However, because the inorganic surface portion 30 maybe inserted into the rigid member RM at the side on which the rigidmember RM is fixed, the width of the display area DA may increase. Insome cases, the passing of moisture and/or oxygen may occur due to thepressure caused by the rigid member RM and/or the internal structure ofthe rigid member RM, the internal moisture and/or oxygen atmosphere ofthe rigid member RM, and/or the internal temperature of the rigid memberRM. In this case, it may be desirable for the width W2 of the inorganicsurface portion 30 at the side fixed by the rigid member RM to berelatively larger than the width W1 of the inorganic surface portion 30at the side not fixed by the rigid member RM.

FIG. 24 is a schematic plan view showing a display device according tostill another example embodiment of the present invention.

Referring to FIG. 24, a display device 1007 is configured such that atleast one pad connected to an external electrical element, such as aflexible printed circuit board (i.e., FPCB), is formed on one side(e.g., the y2 direction side) of the inorganic surface portion 30. Inthis case, the width W2 of the inorganic surface portion 30 adjacent tothe pad at one side (e.g., the y2 direction side) of the display device1007 is relatively smaller than the width W1 of other portions of theinorganic surface portion 30, thereby securing the area where the padsare disposed without unnecessary or excessive reduction of the displayarea DA.

FIG. 25 is a schematic plan view showing a display device according tostill another example embodiment of the present invention.

Referring to FIG. 25, a display device 1008 is configured such that atleast one pad connected to an external electrical element, such as aflexible circuit board, is formed on one side (e.g., the y2 directionside) of the inorganic surface portion 30. In some cases, a plurality ofwirings passes through the inorganic surface portion 30 whileoverlapping with the inorganic surface portion 30. The wirings mayconnect a plurality of circuit structures located relatively inner thanthe inner edge IE of the inorganic surface portion 30 to the padslocated relatively outer than the outer edge OE of the inorganic surfaceportion 30. It may be desired to additionally block moisture, oxygen,impurities, and/or the like that may be introduced from these wirings,and these wirings transmit electrical signals during the operation ofthe display device, so that thermal expansion or thermal contraction mayoccur, which may act as an element to increase the passing of moistureand/or oxygen. Therefore, effective encapsulating may be achieved byincreasing the width W2 of the portion of the inorganic surface portion30 adjacent to the pad relative to the width W1 of the other portions.

FIG. 26 is a schematic plan view showing a display device according tostill another example embodiment of the present invention.

Referring to FIG. 26, a display device 1009 is configured such that theinorganic surface portion 30 located at the same side (e.g., the x2direction side) of the lower structure 100 includes a first region S1having a first width Wa along the x1-x2 directions and a second regionS2 having a second width Wb relatively smaller than the first width Wa.When repeatedly flexing the display device 1009 by bending andstretching it several times, stress relatively that is larger than thatapplied to the second region S2 may be applied to the first region S1adjacent to the bending axis which bisects the display device 1009 alongthe horizontal direction (e.g., the x1-x2 directions). Therefore, thefirst width Wa of the first region S1, which receives more stress, maybe relatively wider than the second width Wb of the second region S2,thereby effectively preventing or reducing the inflow of moisture and/oroxygen. The width of each region of the inorganic surface portion 30located at the same side of the display device 1009 may be adjusteddepending on the stress (e.g., amount of the stress and/or location ofthe stress). In addition, changes in the widths of the respectiveregions of the inorganic surface portion 30 are possible consideringdesign requirement, in addition to the case of considering the stress.

The example embodiments described in FIGS. 21 to 26 are difficult to beimplemented by irradiating a sealant region with a laser. When trying toimplement the example embodiments described in FIGS. 21 to 26 with alaser sealing method, the width of a laser beam should be changed inorder to adjust the width of the inorganic surface portion 30 and thecontact area between the inorganic surface portion 30 and the lowersurface of the flexible encapsulation multilayer. The change in thewidth of a laser beam causes a loss because a laser irradiation deviceand a laser irradiation process should be also changed. Further, asshown in FIG. 26, the change in the width of the inorganic surfaceportion 30 for each region at one side of the display device 1009 ismore difficult to implement. One method to form sealant portions havingwidths different from each other by using a laser beam having thesubstantially same width is varying laser irradiation times from regionsto regions. In this case, to make a width of a part of the sealantportion wider, the part should be irradiated with the laser for arelatively longer time. Therefore, thermal damage may be applied tocircuits, wirings and insulation films adjacent to the sealant portionhaving a relatively large width, and thus this is not preferable.

As described above, when changing the width of the sealant portionthrough single laser beam irradiation, the first width Wa may not beformed at a level of about 110% or more of the second width Wb. Inaddition, because damages may be applied to peripheral circuits,wirings, and/or insulating films in the process, the reliability of thedisplay device may be deteriorated.

On the other hand, according to one or more example embodiments of thepresent invention, the first width Wa may be increased to a level ofabout 110% or more of the second width Wb without laser beamirradiation. In this case, because a laser beam irradiation process isnot used, thermal damage may not occur in the peripheral structures.

In more detail, although not shown in the drawings, the adhesionincreasing recesses that are described in FIGS. 1 to 15 may be formedselectively or more intensively in a portion having a relatively widewidth in FIGS. 21 to 26. The term “selectively” refers to that theadhesion increasing recesses are formed only in that portion, and theterm “more intensively” refers to that the adhesion increasing recessesare formed in that portion at a high density, although they may beformed in other portions as well. In other words, at a region where theadhesion increasing recesses are formed densely, the gaps among theadhesion increasing recesses are comparatively narrow, and at a regionwhere the adhesion increasing recesses are formed less densely, the gapsamong the adhesion increasing recesses are comparatively wide. Further,in some cases, the width of the corner may be made larger or narrower,the adhesion increasing recesses may be formed only at the corner, andthe adhesion increasing recesses may be formed more densely or lessdensely at the corner.

FIG. 27 is a schematic plan view showing a display device according tostill another example embodiment of the present invention. FIG. 28 is aschematic plan view showing a display device according to still anotherexample embodiment of the present invention, which is a plan viewshowing a modified structure of FIG. 27.

Referring to FIG. 27, a display device 1010 includes an alignment markAM1 or AM2. The alignment mark AM1 or AM2 is located relatively inwardrelative to the outer edge of the inorganic surface portion 30. At aplanar view, the alignment mark AM1 or AM2 is disposed to overlap withthe inorganic surface portion 30. Therefore, the area of the peripheralarea PA may be effectively reduced compared to when the alignment markAM1 or AM2 is disposed relatively outward relative to the outer edge ofthe inorganic surface portion 30.

The alignment mark AM1 or AM2 may be an inorganic material patternhaving optical reflectivity, for example, a metal pattern. Thus, thealignment mark AM1 or AM2 is easy to optically discriminate. However,the alignment mark AM1 or AM2 is not particularly limited as long as itmay be optically left-right discriminated, and may be cross-shaped insome example embodiments.

The alignment mark AM1 or AM2 may be a first alignment mark AM1 or asecond alignment mark AM2. The first alignment mark AM1 may be a holeformed through a metal film, and the second alignment mark AM2 is ametal pattern having no hole. The display device 1010 may include boththe first and second alignment marks AM1 and AM2. Alternatively, thedisplay device 1010 may include one of the first and second alignmentmarks AM1 and AM2.

When the first alignment mark AM1 is employed in the display device1010, the first alignment mark AM1 may be a hole formed through a dummymetal film. Alternatively, the hole may also be formed by drilling ametal film, such as a wire for transmitting an electric signal fordriving the electroluminescent unit EU. In the case of forming the firstalignment marks AM1 by drilling a separate wire or the like, a space maybe advantageously saved as compared to the case of forming a separatedummy metal film.

For example, the first alignment mark AM1 may be formed through the buswire 109 b of FIGS. 17 and 20. In this case, the adhesion increasingrecess 50 a shown in FIG. 1 may also be formed through the bus wire 109b. That is, although a plurality of holes are formed through the buswire 109 b, some of the holes may be used as the adhesion increasingrecess 50 a, and others of the holes may be used as the first alignmentmark AM1. Here, the holes used as the first alignment mark AM1 as wellas the holes used as the adhesion increasing recess 50 a may improveadhesion. In this case, the planar shape of the adhesion increasingrecess 50 a and the planar shape of the first alignment mark AM1 may bedifferent from each other.

The upper surface or lateral surface of the first alignment mark AM1 maybe included in the inorganic surface portion 30 to be in contact withthe bottom surface of the flexible encapsulation multilayer 210. In thiscase, the first alignment mark AM1 serves as a kind of unevenness toincrease the adhesion with the flexible encapsulation multilayer 210.

When the first alignment mark AM1 is formed through the bus wire 109 b,as shown in FIG. 18, the first alignment mark AM1 may be formed underthe inorganic surface portion 30. In this case, the first alignment markAM1 may not be damaged in the process of forming the flexibleencapsulation multilayer 210. Even in this case, the adhesion increasingrecess 50 a may be additionally formed in the bus wire 109 b. Even ifthe adhesion increasing recess 50 a is not in direct contact with theinorganic surface portion 30, it is located under the inorganic surfaceportion 30, so that the inorganic surface portion 30 may be providedwith unevenness indirectly. That is, referring to FIG. 18, the surfaceof the inorganic film 114 included in the inorganic surface portion 30may be provided with unevenness due to the adhesion increasing recess 50a formed through the bus wire 109 b.

FIG. 28 is a plan view showing a modified structure of FIG. 27. As shownin FIG. 28, a display device 1011, unlike the display device 1010 shownin FIG. 27, is configured such that the alignment mark AM1 or AM2 isdisposed inward (e.g., more toward a center of the display device 1011)relative to an inner edge IE of the inorganic surface portion 30, whichis opposite to an outer edge OE of the inorganic surface portion 30.

Because the display device 1011 is configured such that the alignmentmark AM1 or AM2 is disposed closer to the display area DA, more precisealignment may be possible in the alignment process necessary for formingthe display area DA.

Details of the alignment mark AM1 or AM2 will not be repeated becausethey are substantially the same or substantially the same as thosedescribed with reference to FIG. 27.

FIG. 29 is a schematic plan view showing a display device according tostill another example embodiment of the present invention, and FIG. 30is an enlarged view of the area T of FIG. 29.

Referring to FIGS. 17, 29, and 30, the display device 1011 includes anupper electrode power supply wire 901 electrically connected to theupper electrode 125 of the electroluminescent unit EU to apply anelectric signal to the upper electrode 125, and a lower electrode powersupply wire 902 electrically connected to the lower electrode 121 of theelectroluminescent unit EU to apply an electric signal to the lowerelectrode 121. Here, the upper electrode power supply wire 901 mayinclude a bus wire 109 b and an auxiliary upper electrode 106 c.

An upper electrode power supply terminal 901 t and a lower electrodepower supply terminal 902 t are located at the ends of the upperelectrode power supply wire 901 and the lower electrode power supplywire 902, respectively.

The upper electrode power supply terminal 901 t and the lower electrodepower supply terminal 902 t may be disposed along one direction (e.g.,the x1-x2 directions). Further, the upper electrode power supplyterminal 901 t and the lower electrode power supply terminal 902 t maybe electrically connected to one external circuit board. Here, anexample of the external circuit board may be a flexible circuit board.

The peripheral area PA may have a bendable area BA. For example, thebendable area BA may be provided between the display area DA and atleast one of the lower electrode power supply terminal 902 t and theupper electrode power supply terminal 901 t.

When the bendable area BA is bent, the external circuit board connectedto at least one of the lower electrode power supply terminal 902 t andthe upper electrode power supply terminal 901 t may be fixed on a backsurface of the display device 1011.

The lower electrode power supply wire 902 and the upper electrode powersupply wire 901 may include a conductive bridge 902 b and a conductivebridge 901 b. The conductive bridges 902 b and 901 b may have contactsCnt and cross the bendable area BA. The conductive bridge 902 b may belocated on a different layer from a portion of the adjacent lowerelectrode power supply wire 902. Similarly, the conductive bridge 901 bmay be located on a different layer from a portion of the adjacent upperelectrode power supply wire 901. When the conductive bridges 902 b and901 b are used, the bendable area BA may be bent more easily.

Although not specifically shown in the drawings, the sum of thethicknesses of insulating layers in the bendable area BA is maderelatively smaller than the sum of the thicknesses of the insulatinglayers in the peripheral area PA adjacent to the bendable area BA, tobend the bendable region BA more easily.

The peripheral area PA has an inorganic surface portion 30 of a closedshape surrounding (e.g., continuously surrounding) the display area DA.

The inorganic surface portion 30 has a region that is branched into aplurality of inorganic surface branches Br1, Br2, Br3, Br4 and Br5 thatare spaced from each other.

The peripheral area PA may include organic surface portions Os1, Os2,Os3 and Os4 located between the inorganic surface branches Br1, Br2,Br3, Br4 and Br5 of the inorganic surface portion 30. Here, the organicsurface portions Os1, Os2, Os3 and Os4 are surrounded (e.g., completelysurrounded) by the inorganic-inorganic direct bonding between the lowersurface of the flexible encapsulation multilayer 210 and the inorganicsurface portion 30. These organic surface portions Os1, Os2, Os3 and Os4absorb the impurities that may move along the interface between thelower surface of the flexible encapsulation multilayer 210 and theinorganic surface portion 30, and then keep holding these impurities,thereby lowering the concentration of the impurities existing at theinterface between the lower surface of the flexible encapsulationmultilayer 210 and the inorganic surface portion 30. Therefore, thereliability of the inorganic-inorganic direct bonding may increase.

When the organic surface portions Os1, Os2, Os3 and Os4 are relativelyfar from the impurities that may exist at the interface where theinorganic surface portion 30 and the lower surface of the flexibleencapsulation multilayer 210 make the inorganic-inorganic directionbonding, the impurities may be concentrated on a certain part of theinterface before the impurities move to the organic surface portionsOs1, Os2, Os3 and Os4. Therefore, the bonding force of theinorganic-inorganic direct bonding decreases. In addition, theseimpurities move to the display area DA before the impurities move to theorganic surface portions Os1, Os2, Os3 and Os4. Therefore, anintermediate layer included in the electroluminescent unit EU located inthe display area DA is deteriorated.

When the display area DA has a flexible portion and the flexible portionis bent and then unbent (e.g., stretched) repeatedly or folded andstretched repeatedly, it more frequently occurs that the impurities areconcentrated at a part (or portion) of the interface or the impuritiesmove to the display area DA.

Here, the case of the display area DA having a flexible portion refersto that the lower structure 100 may be used as any one of a bendabledisplay substrate, a foldable display substrate, a rollable displaysubstrate, a stretchable display substrate, and a flexible displaysubstrate. However, the present invention is not limited thereto, andone or more example embodiments of the present invention may be appliedeven to a display device employing the flexible encapsulation multilayer210 while having no flexible portion. Illustratively, exampleembodiments of the present invention may be applied even to a flatdisplay device having a flexible encapsulation multilayer and fixed to aflat rigid window and a curved display device having a flexibleencapsulation multilayer and fixed to a curved rigid window.

In order to reduce the distance between the organic surface portionsOs1, Os2, Os3 and Os4 and the impurities located at the interface formedby the inorganic-inorganic direct bonding, the organic surface portionsOs1, Os2, Os3 and Os4 may have a shape that surrounds or substantiallysurrounds the display area DA.

Here, the meaning of that phrase the organic surface portions Os1, Os2,Os3 and Os4 “surrounds or substantially surrounds the display area DA”includes not only the case of the organic surface portions Os1, Os2, Os3and Os4 shown in FIG. 29, the organic surface portion Os4 shown in FIG.32, and the organic surface portion Os4 shown in FIG. 33, whichcontinuously surround the display area DA, but also the case of theorganic surface portions Os1, Os2, Os3 and Os4 shown in FIG. 31, theorganic surface portions Os1, Os2, and Os3 shown in FIG. 32, and theorganic surface portions Os1, Os2, and Os3 shown in FIG. 33, whichdiscontinuously surround the display area DA.

When the display area DA has a shape having two or less outer sides,such as a circle, an ellipse, and a semicircle, for example, the case ofthe organic surface portion Os continuously or discontinuouslysurrounding the display area DA refers to that the organic surfaceportion Os continuously or discontinuously extends to correspond to ¼ ormore of the entire outer periphery of the display area DA. Further, whenthe shape of the display area DA is a triangle, for example, the case ofthe organic surface portion Os continuously or discontinuouslysurrounding the display area DA refers to that the organic surfaceportion Os continuously or discontinuously extends to correspond to atleast one outer side of the display area DA. Furthermore, when the shapeof the display area DA is a square, a pentagon, a hexagon, or the like,the case of the organic surface portion Os continuously ordiscontinuously surrounding the display area DA refers to that theorganic surface portion Os continuously or discontinuously extends tocorrespond to at least two outer sides of the display area DA.

Because the organic surface portions Os1, Os2, Os3 and Os4 aresurrounded (e.g., completely surrounded) by the inorganic-inorganicdirect bonding at a planar view, they do not communicate with theoutside of the display device 1011. Therefore, moisture or impuritiesmay not be supplied to the interface formed by the inorganic-inorganicdirect bonding from the outside of the display device through theorganic surface portions Os1, Os2, Os3 and Os4.

Each of the organic surface portions Os1, Os2, Os3 and Os4 may have asectional shape protruding upward. Further, each of the organic surfaceportions Os1, Os2, Os3 and Os4 may have various shapes, such as, forexample, an island shape, a shape extending along the direction in whichthe inorganic surface portion 30 extends, and the like.

The height of the organic surface portions Os1, Os2, Os3 and Os4 may bethe same or substantially the same as the height of the pixel defininglayer 117. Although not shown, the height of the pixel defining layer117 may include the height of a spacer protruding upward from the top ofthe pixel defining layer 117.

When the height of the organic surface portions Os1, Os2, Os3 and Os4may be substantially the same as the height of the pixel defining layer117, the organic surface portions Os1, Os2, Os3 and Os4 may be used asspacers that may be in contact with an evaporation mask in a vacuumevaporation process for forming the intermediate layer of theelectroluminescent unit EU. In more detail, the hole injection layer(HIL), hole transport layer (HTL), electron injection layer (EIL) andelectron transport layer (ETL) included in the intermediate layer may beformed as a common layer. In this case, the organic surface portion maybe used as a spacer of an open evaporation mask.

As described above, the organic surface portions Os1, Os2, Os3 and Os4may have a closed loop shape surrounding (e.g., continuouslysurrounding) the display area DA. In this case, because an entire edgeof the deposition mask may correspond to the organic surface portionsOs1, Os2, Os3 and Os4, the organic materials passing through theevaporation mask may not escape from the space defined by a depositiontarget region of the lower structure 100, the evaporation mask, and theorganic surface portions Os1, Os2, Os3 and Os4 during the evaporationprocess.

FIG. 31 is a schematic plan view showing a display device according tostill another example embodiment of the present invention. Referring toFIG. 31, a display device 1012 is different from the display device 1011of FIGS. 29 and 30, as the shape of the organic surface portions Os1,Os2, Os3 and Os4 are different. In more detail, the organic surfaceportions Os1, Os2, Os3 and Os4 of the display device 1012 may have anopened loop shape. For example, the organic surface portions Os1, Os2,Os3 and Os4 may be opened by at least one of openings Op1, Op2, Op3 andOp4 in order to discontinuously surround the display area DA. When theinorganic surface branches Br1, Br2, Br3, Br4 and Br5 of the inorganicsurface portion 30 are not connected to each other, at least one of theinorganic surface branches Br1, Br2, Br3, Br4 and Br5 of the inorganicsurface portion 30 may be independently detached from the lower surfaceof the flexible encapsulation multilayer 200 when excessive physicalstress is applied to the display device 1012. However, according toexample embodiments of the present invention, because the inorganicsurface branches Br1, Br2, Br3, Br4 and Br5 of the inorganic surfaceportion 30 are connected to each other, the inorganic direct bonding maybe effective.

When the organic surface portions Os1, Os2, Os3 and Os4 have an openloop shape, there are no organic surface portions Os1, Os2, Os3 and Os4in regions of the inorganic surface portion 30 corresponding to theopenings Op1, Op2, Op3 and Op4. Accordingly, impurities located at thebonding interface in the regions of the inorganic surface portion 30corresponding to the openings Op1, Op2, Op3 and Op4 may be easilyconcentrated on a certain part of the interface. Therefore, the bondingforce of the inorganic surface portion 30 may be relatively lower than acase where there is no the openings Op1, Op2, Op3 and Op4. Therefore,the width of the inorganic surface portion 30 at the first side(illustratively, in the y2 direction side) of the lower structure 100provided with the openings Op1, Op2, Op3 and Op4 may be relativelylarger than the width of the inorganic surface portion 30 at the secondside (illustratively, in the x2 direction side) of the lower structure100 not provided with the openings Op1, Op2, Op3 and Op4. Thus, thebonding force at the first side (e.g., the y2 direction side) of thelower structure 100 may be enhanced.

FIG. 32 is a schematic plan view showing a display device according tostill another example embodiment of the present invention. Referring toFIG. 32, a display device 1013 is different from the display device 1012of FIG. 31, as the shape of the organic surface portions Os1, Os2, Os3and Os4 are different.

Referring to FIG. 32, the lower structure 100 of the display device 1013may include organic surface portions Os1, Os2, and Os3 each having anopen loop shape and an organic surface portion Os4 having a closed loopshape.

FIG. 33 is a schematic plan view showing a display device according tostill another example embodiment of the present invention. Referring toFIG. 33, a display device 1014 is different from the display device 1013of FIG. 32, as the shape of the organic surface portion Os4 isdifferent.

Referring to FIG. 33, when some organic surface portions Os1, Os2 andOs3 of the organic surface portions Os1, Os2, Os3 and Os4 are surrounded(e.g., completely surrounded) by the direct bonding between the lowersurface of the flexible encapsulation multilayer 210 and the inorganicsurface portion 30 at a planar view, the remaining organic surfaceportion Os4 may communicate with the outside of the display device 1014.

In more detail, the lower structure 100 may include a first organicsurface portion Os4 having a closed loop shape that communicates withthe outside and second organic surface portions Os1, Os2, and Os3 thatare disposed between the first organic surface portion Os4 and thedisplay area DA. The second organic surface portions Os1, Os2, and Os3may have an open loop shape and may be surrounded (e.g., completelysurrounded) by the direction bonding between the lower surface of theflexible encapsulation multilayer 200 and the inorganic surface portion30 at a planar view.

In this case, the height of the first organic surface portion Os4 is thesame or substantially the same as that of the pixel defining layer 117,and thus may serve as a spacer for the evaporation mask. The widths ofthe second organic surface portions Os1, Os2 and Os3 may be effectivelylowered by making the height of the second organic surface portions Os1,Os2 and Os3 relatively lower than the height of the first organicsurface portion Os4. Therefore, the width of the peripheral area PA maybe narrowed.

The organic surface portions Os1 and Os2 may extend to cover the lateralsides of wirings. The wirings may be a conductive multilayer. Becausethe lateral portions of the conductive multilayer are susceptible tocorrosion because a plurality of interfaces are exposed, the organicsurface portions Os1 and Os2 may prevent or reduce the corrosion of theconductive multilayer by covering the lateral sides of the conductivemultilayer. In addition, the organic surface portions Os1 and Os2 mayabsorb the impurities, such as moisture, oxygen, and the like, which maybe discharged from the interfaces exposed at the lateral sides of theconductive multilayer, and may hold these impurities.

As an example, the conductive multilayer may be an auxiliary upperelectrode 106 c which is the same film as the lower electrode 121 of theelectroluminescent unit EU, and the lateral side of the auxiliary upperelectrode 106 c may be covered by the organic surface portion Os1. Inthis case, the auxiliary upper electrode 106 c may include a firstconductive indium tin oxide film, a silver (Ag) film on the firstconductive indium tin oxide film, and a second conductive indium tinoxide film on the silver film.

As another example, the conductive multilayer may be a bus wire 109 bwhich is the same film as the source electrode 105 or drain electrode107 of the thin film transistor TFT, and the lateral side of the buswire 109 b may be covered by the organic surface portion Os2. The buswire 109 b may be the same film as the source electrode 105 or drainelectrode 107 of the thin film transistor (PC-TFT). In this case, thebus wire 106 b may include a first titanium (Ti) film, an aluminum (Al)film formed on the first titanium film, and a second titanium filmformed on the aluminum film, or may include a first molybdenum (Mo)film, an aluminum film on the first molybdenum film, and a secondmolybdenum film on the aluminum film. As still another example, theconductive multilayer may be the same film as the gate electrode 103 ofthe thin film transistor located in the display area DA.

As described above, according to one or more example embodiments of thepresent invention, a display device having improved encapsulatingcharacteristics may be provided.

Although the present invention has been described with reference to theexample embodiments, those skilled in the art will recognize thatvarious changes and modifications to the described example embodimentsmay be performed, all without departing from the spirit and scope of thepresent invention. Furthermore, those skilled in the various arts willrecognize that the present invention described herein will suggestsolutions to other tasks and adaptations for other applications. It isthe applicant's intention to cover by the claims herein, all such usesof the present invention, and those changes and modifications whichcould be made to the example embodiments of the present invention hereinchosen for the purpose of disclosure, all without departing from thespirit and scope of the present invention. Thus, the example embodimentsof the present invention should be considered in all respects asillustrative and not restrictive, with the spirit and scope of thepresent invention being indicated by the appended claims, and theirequivalents.

What is claimed is:
 1. An electroluminescent device comprising: a lowerstructure which has an emission area and a peripheral area surroundingthe emission area, and which comprises an inorganic insulating film, aninsulation film located on the inorganic insulating film, and anelectroluminescent unit having a lower electrode disposed on theinsulation film, an intermediate film disposed on the lower electrode,and an upper electrode disposed on the intermediate film, and a flexibleencapsulation multilayer disposed on the emission area and theperipheral area, and including at least three layers, wherein theperipheral area includes an inorganic surface portion substantiallysurrounding the emission area, located outside the upper electrode at aplanar view, and comprising only one or more inorganic materials,wherein the flexible encapsulation multilayer includes a lower surfacecomprising only one or more inorganic materials, wherein an entire ofthe inorganic surface portion directly contacts the lower surface of theflexible encapsulation multilayer, wherein the lower structure includesa lower encapsulation inorganic film horizontally expanding under asurface of the lower structure to vertically correspond to the emissionarea and the peripheral area, and a portion disposed between the lowerencapsulation inorganic film and the entire of the inorganic surfaceportion comprises only one or more inorganic materials, and wherein theinorganic surface portion includes a first region having a first averagewidth and a second region having a second average width, and the firstaverage width and the second average width are substantially differentfrom each other.
 2. The electroluminescent device of claim 1, whereinthe first region and the second region are located at the same side ofthe lower structure.
 3. The electroluminescent device of claim 2,wherein the electroluminescent device is capable of being flexed, bent,folded, rolled, or stretched by an end user.
 4. The electroluminescentdevice of claim 1, wherein the first region of the inorganic surfaceportion entirely corresponds to a first side of the lower structure, andthe second region of the inorganic surface portion entirely correspondsto a second side of the lower structure different from the first side ofthe lower structure.
 5. The electroluminescent device of claim 4,wherein the first region has a first part having a third average widthrelatively smaller than the first average width and a second part havinga fourth average width relatively larger than the first average width.6. The electroluminescent device of claim 5, wherein theelectroluminescent device is capable of being flexed, bent, folded,rolled, or stretched by an end user.
 7. The electroluminescent device ofclaim 4, wherein the electroluminescent device is capable of beingflexed, bent, folded, rolled, or stretched by an end user.
 8. Theelectroluminescent device of claim 1, wherein the lower electrode isdisposed directly on a top surface of the insulation film, and theentire of the inorganic surface portion is disposed relatively lowerthan the top surface of the insulation film, wherein the inorganicsurface portion has at least a region including a plurality of inorganicsurface branches spaced from each other, wherein the peripheral areaincludes an organic surface portion which is disposed between theinorganic surface branches, which comprises an organic material, whichsubstantially surrounds the emission area, and which is substantiallysurrounded at a planar view by an interface where the lower surface ofthe flexible encapsulation multilayer directly contacts the inorganicsurface portion, wherein the inorganic surface branches include an outerinorganic surface branch located relatively outer than the organicsurface portion and an inner inorganic surface branch located relativelyinner than the organic surface portion, wherein the lower structurefurther comprises a bus wire extending on a top surface of the inorganicinsulating film along a periphery of the emission area, and an auxiliaryupper electrode which extends on side and top surfaces of the insulationfilm along the periphery of the emission area, has a bottom surfaceelectrically facing a top surface of the bus wire to electricallycommunicate with the top surface of the bus wire, and has a top surfaceelectrically facing a bottom surface of the upper electrode toelectrically communicate with the bottom surface of the upper electrode,wherein the inner inorganic surface branch includes at least a portionof a top surface of the auxiliary upper electrode to have a heightrelatively larger than a height of the outer inorganic surface branch,and wherein a portion of a surface of the bus wire directly contacts thelower surface of the flexible encapsulation multilayer, and the portionof the surface of the bus wire is relatively farther than the organicsurface portion from the emission area.
 9. The electroluminescent deviceof claim 8, wherein the electroluminescent device is capable of beingflexed, bent, folded, rolled, or stretched by an end user.
 10. Theelectroluminescent device of claim 8, wherein the inorganic surfaceportion includes at least two stepped surface portions each including atop surface portion of the inorganic insulating film, a side surfaceportion of the bus wire, and a top surface portion of the bus wire, andwherein the bus wire has an outer edge portion and an inner edge portionopposite to the outer edge portion, the outer edge portion of the buswire is relatively farther than the inner edge portion of the bus wirefrom the emission area, the outer edge portion of the bus wire islocated under the bottom surface of the flexible encapsulationmultilayer, and the outer edge portion of the bus wire is not in directcontact with the bottom surface of the flexible encapsulationmultilayer.
 11. The electroluminescent device of claim 10, wherein theinorganic surface portion further includes at least two stepped surfaceportions each including a top surface portion of the inorganicinsulating film, a side surface portion of the auxiliary upperelectrode, and a top surface portion of the auxiliary upper electrode,and wherein the auxiliary upper electrode has an outer edge portion andan inner edge portion opposite to the outer edge portion, the outer edgeportion of the auxiliary upper electrode is relatively farther than theinner edge portion of the auxiliary upper electrode from the emissionarea, the outer edge portion of the auxiliary upper electrode is locatedunder the bottom surface of the flexible encapsulation multilayer, andthe outer edge portion of the auxiliary upper electrode is not in directcontact with the bottom surface of the flexible encapsulationmultilayer.
 12. The electroluminescent device of claim 11, wherein theelectroluminescent device is capable of being flexed, bent, folded,rolled, or stretched by an end user.
 13. The electroluminescent deviceof claim 10, wherein the inorganic surface portion further includes atleast two stepped surface portions each including a top surface portionof the bus wire, a side surface portion of the auxiliary upperelectrode, and a top surface portion of the auxiliary upper electrode,and wherein the auxiliary upper electrode has an outer edge portion andan inner edge portion opposite to the outer edge portion, the outer edgeportion of the auxiliary upper electrode is relatively farther than theinner edge portion of the auxiliary upper electrode from the emissionarea, the outer edge portion of the auxiliary upper electrode is locatedunder the bottom surface of the flexible encapsulation multilayer, andthe outer edge portion of the auxiliary upper electrode is not in directcontact with the bottom surface of the flexible encapsulationmultilayer.
 14. The electroluminescent device of claim 13, wherein theelectroluminescent device is capable of being flexed, bent, folded,rolled, or stretched by an end user.
 15. The electroluminescent deviceof claim 10, wherein the inorganic surface portion further includes atleast two stepped surface portions each including a top surface portionof the inorganic insulating film, a side surface portion of theauxiliary upper electrode, and a top surface portion of the auxiliaryupper electrode, wherein the inorganic surface portion further includesat least two stepped surface portions each including a top surfaceportion of the bus wire, a side surface portion of the auxiliary upperelectrode, and a top surface portion of the auxiliary upper electrode,and wherein the auxiliary upper electrode has an outer edge portion andan inner edge portion opposite to the outer edge portion, the outer edgeportion of the auxiliary upper electrode is relatively farther than theinner edge portion of the auxiliary upper electrode from the emissionarea, the outer edge portion of the auxiliary upper electrode is locatedunder the bottom surface of the flexible encapsulation multilayer, andthe outer edge portion of the auxiliary upper electrode is not in directcontact with the bottom surface of the flexible encapsulationmultilayer.
 16. The electroluminescent device of claim 15, wherein theelectroluminescent device is capable of being flexed, bent, folded,rolled, or stretched by an end user.
 17. The electroluminescent deviceof claim 10, wherein the electroluminescent device is capable of beingflexed, bent, folded, rolled, or stretched by an end user.
 18. Theelectroluminescent device of claim 8, wherein the portion of the surfaceof the bus wire, which directly contacts the lower surface of theflexible encapsulation multilayer, is included in the outer inorganicsurface branch.
 19. The electroluminescent device of claim 18, whereinthe electroluminescent device is capable of being flexed, bent, folded,rolled, or stretched by an end user.
 20. The electroluminescent deviceof claim 8, wherein the organic surface portion has a shape opened by anopening to discontinuously surround the emission area, wherein the firstregion of the inorganic surface portion entirely corresponds to a firstside of the lower structure at which the opening is disposed, whereinthe second region of the inorganic surface portion entirely correspondsto a second side of the lower structure at which the opening is notdisposed, and wherein the first average width of the first region isrelatively larger than the second average width of the second region.21. The electroluminescent device of claim 20, wherein theelectroluminescent device is capable of being flexed, bent, folded,rolled, or stretched by an end user.
 22. The electroluminescent deviceof claim 1, wherein the electroluminescent device is capable of beingflexed, bent, folded, rolled, or stretched by an end user.
 23. Anelectroluminescent device comprising: a lower structure which has anemission area and a peripheral area surrounding the emission area, andwhich comprises an inorganic insulating film, an insulation film locatedon the inorganic insulating film, and an electroluminescent unit havinga lower electrode disposed on the insulation film, an intermediate filmdisposed on the lower electrode, and an upper electrode disposed on theintermediate film, and a flexible encapsulation multilayer disposed onthe emission area and the peripheral area, and including at least threelayers, wherein the peripheral area includes an inorganic surfaceportion substantially surrounding the emission area, located outside theupper electrode at a planar view, and comprising only one or moreinorganic materials, wherein the flexible encapsulation multilayerincludes a lower surface comprising only one or more inorganicmaterials, wherein an entire of the inorganic surface portion directlycontacts the lower surface of the flexible encapsulation multilayer,wherein the lower structure includes a lower encapsulation inorganicfilm horizontally expanding under a surface of the lower structure tovertically correspond to the emission area and the peripheral area, anda portion disposed between the lower encapsulation inorganic film andthe entire of the inorganic surface portion comprises only one or moreinorganic materials, wherein the peripheral area includes an inorganicstructure having an edge having a lateral surface and an upper surface,wherein the inorganic surface portion includes the lateral and uppersurfaces of the edge, wherein the lateral and upper surfaces of the edgedirectly contact the flexible encapsulation multilayer, wherein the edgeextends from an outer edge of the inorganic surface portion to an inneredge of the inorganic surface portion located opposite to the outer edgeof the inorganic surface portion, and wherein the lateral surface of theedge includes at least two independently selected from the groupconsisting of a convex portion, a concave portion, an angled portion, acurved portion, and a portion extending substantially along a directionin which the inorganic surface portion extends.
 24. Theelectroluminescent device of claim 23, wherein the inorganic structureincludes a first inorganic film and a second inorganic film disposed onthe first inorganic film, and wherein a hardness of the second inorganicfilm is relatively larger than a hardness of the first inorganic film.25. The electroluminescent device of claim 24, wherein theelectroluminescent device is capable of being flexed, bent, folded,rolled, or stretched by an end user.
 26. The electroluminescent deviceof claim 23, wherein the electroluminescent device is capable of beingflexed, bent, folded, rolled, or stretched by an end user.
 27. Anelectroluminescent device comprising: a lower structure which has anemission area and a peripheral area surrounding the emission area, andwhich comprises an inorganic insulating film, an insulation film locatedon the inorganic insulating film, and an electroluminescent unit havinga lower electrode disposed on the insulation film, an intermediate filmdisposed on the lower electrode, and an upper electrode disposed on theintermediate film, and a flexible encapsulation multilayer disposed onthe emission area and the peripheral area, and including at least threelayers, wherein the peripheral area includes an inorganic surfaceportion substantially surrounding the emission area, located outside theupper electrode at a planar view, and comprising only one or moreinorganic materials, wherein the flexible encapsulation multilayerincludes a lower surface comprising only one or more inorganicmaterials, wherein an entire of the inorganic surface portion directlycontacts the lower surface of the flexible encapsulation multilayer,wherein the lower structure includes a lower encapsulation inorganicfilm horizontally expanding under a surface of the lower structure tovertically correspond to the emission area and the peripheral area, anda portion disposed between the lower encapsulation inorganic film andthe entire of the inorganic surface portion comprises only one or moreinorganic materials, wherein the peripheral area includes a conductivefilm providing the electroluminescent unit with an electrical signal,and having a hole which penetrates the conductive film, which is locatedinward from an inner edge of the inorganic surface portion, and which isan alignment mark, and wherein the conductive film is an auxiliary upperelectrode extending along a periphery of the emission area, and having atop surface electrically facing a bottom surface of the upper electrodeto electrically communicate with the bottom surface of the upperelectrode.
 28. The electroluminescent device of claim 27, wherein theelectroluminescent device is capable of being flexed, bent, folded,rolled, or stretched by an end user.
 29. An electroluminescent devicecomprising: a lower structure which has an emission area and aperipheral area surrounding the emission area, and which comprises aninorganic insulating film, an insulation film located on the inorganicinsulating film, and an electroluminescent unit having a lower electrodedisposed on the insulation film, an intermediate film disposed on thelower electrode, and an upper electrode disposed on the intermediatefilm, and a flexible encapsulation multilayer disposed on the emissionarea and the peripheral area, and including at least three layers,wherein the peripheral area includes an inorganic surface portionsubstantially surrounding the emission area, located outside the upperelectrode at a planar view, and comprising only one or more inorganicmaterials, wherein the flexible encapsulation multilayer includes alower surface comprising only one or more inorganic materials, whereinan entire of the inorganic surface portion directly contacts the lowersurface of the flexible encapsulation multilayer, wherein the lowerstructure includes a lower encapsulation inorganic film horizontallyexpanding under a surface of the lower structure to verticallycorrespond to the emission area and the peripheral area, and a portiondisposed between the lower encapsulation inorganic film and the entireof the inorganic surface portion comprises only one or more inorganicmaterials, wherein the inorganic surface portion has at least onerecess, wherein the recess is a hole formed through a first inorganiclayer on a second inorganic layer such that a top surface of the secondinorganic layer is exposed through the hole and becomes a bottom surfaceof the recess, and wherein the first inorganic layer comprises only oneor more inorganic films, and the second inorganic layer comprises onlyone or more inorganic films.
 30. The electroluminescent device of claim29, wherein the recess has a protrusion having a height no more than adepth of the recess.
 31. The electroluminescent device of claim 29,wherein at least two of the recesses have substantially different shapesin a plan view.